Microscope objective

Abstract

The application relates to a microscope objective, comprising three part lens groups arranged in sequence from the object side to the image side, the first part lens group comprising a first lens group and a second lens group arranged in sequence from the object to the image, the focal power of the first lens group being negative, and the focal power of the second lens group being negative; the second part lens group comprising a third lens group and a fourth lens group arranged in sequence from the object to the image, the focal power of the third lens group being positive, and the focal power of the fourth lens group being positive; the third part lens group comprising a fifth lens group and a sixth lens group arranged in sequence from the object to the image, the focal power of the fifth lens group being positive, and the focal power of the sixth lens group being positive; the microscope objective satisfying: 3

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microscope objective, in particular to a microscope objective. BACKGROUND

[0002] Due to the increasing requirements of observation resolution and imaging speed in the field of life science and industry, the trend of microscope objective is larger field of view and larger numerical aperture (NA). While realizing large numerical aperture and complex achromatism, it is also necessary to ensure the long working distance of the microscope objective, and the structure has good machinability. It plays an important role in the production of large numerical aperture and ultra-long working distance microscope objective, especially in the special use scenarios of metallographic microscope and biological microscope. The demand for such microscope objective is increasing. SUMMARY

[0003] Based on the fact that the existing microscope objective cannot meet the requirements of realizing large numerical aperture and complex achromatism while ensuring the long working distance of the microscope objective, it is necessary to provide a microscope objective.

[0004] A microscope objective, comprising, arranged in order from object side to image side:

[0005] a first part lens group, comprising a first lens group and a second lens group arranged in order from object side to image side, the focal power of the first lens group is negative, and the focal power of the second lens group is negative;

[0006] a second part lens group, comprising a third lens group and a fourth lens group arranged in order from object side to image side, the focal power of the third lens group is positive, and the focal power of the fourth lens group is positive;

[0007] a third part lens group, comprising a fifth lens group and a sixth lens group arranged in order from object side to image side, the focal power of the fifth lens group is positive, and the focal power of the sixth lens group is positive;

[0008] In particular, the microscope objective satisfies:

[0009] 4.5 < D / fobj < 4.6;

[0010] fobj > 20; and

[0011] 0.2 < NA < 0.325;

[0012] Wherein, D is the distance from the object plane to the image side of the sixth lens group; fobj is the focal length of the microscope objective; NA is the object side numerical aperture of the microscope objective.

[0013] In some embodiments of the present application, the first mirror group comprises a first lens and a second lens which are cemented to each other, the object side surface and the image side surface of the first lens are both concave, and the object side surface of the second lens is convex and the image side surface of the second lens is concave.

[0014] The focal length of the first lens fL1, the radius of curvature of the image side surface of the first lens RL1, and the focal length of the microscope objective fobj satisfy: 0.72≤|fL1 / fobj|≤0.74, 0.79≤|RL1 / fobj|≤0.99.

[0015] In some embodiments of the present application, the second mirror group comprises a third sub-lens and a third sub-sub-lens which are cemented to each other, the object side surface of the third sub-lens is concave, the image side surface of the third sub-lens is a plane, the object side surface of the third sub-sub-lens is a plane, and the image side surface of the third sub-sub-lens is convex.

[0016] In some embodiments of the present application, the third mirror group comprises a fourth lens, a fifth lens, and a sixth lens which are cemented to each other in order from the object side to the image side, the object side surface of the fourth lens is a plane and the image side surface of the fourth lens is convex, the object side surface and the image side surface of the fifth lens are both concave, and the object side surface and the image side surface of the sixth lens are both convex.

[0017] The fourth mirror group comprises a seventh lens, an eighth lens, and a ninth lens which are cemented to each other in order from the object side to the image side, the object side surface and the image side surface of the seventh lens are both convex, the object side surface and the image side surface of the eighth lens are both concave, and the object side surface and the image side surface of the ninth lens are both convex.

[0018] In some embodiments of the present application, the fifth lens and / or the eighth lens are made of a low dispersion material.

[0019] In some embodiments of the present application, the fifth mirror group comprises a tenth lens, the object side surface of the tenth lens is convex, and the image side surface of the tenth lens is a plane, and the sixth mirror group comprises an eleventh lens, the object side surface of the eleventh lens is convex, and the image side surface of the eleventh lens is concave.

[0020] In some embodiments of the present application, the minimum projection height H1 of the central field of view edge light on the lens surface in the third partial mirror group, the maximum projection height H2 of the central field of view edge light on the lens surface in the second partial mirror group, and the projection height H3 of the central field of view edge light on the lens surface closest to the image side in the first partial mirror group satisfy: 0.92<|H2 / H3|<1.07, 1.79<|H1 / H2|<1.89.

[0021] In some embodiments of the present application, the focal length fT1 of the first partial mirror group and the focal length fobj of the microscope objective satisfy: 1.45≤|fT1 / fobj|≤1.48.

[0022] In some embodiments of the present application, the focal length fT2 of the second partial mirror group and the focal length fobj of the microscope objective satisfy: 3.52≤|fT2 / fobj|≤3.58.

[0023] In some embodiments of the present application, the focal length fT3 of the third partial mirror group and the focal length fobj of the microscope objective satisfy: 1.68≤|fT3 / fobj|≤1.69.

[0024] In summary, the microscope objective of the present application optimizes and corrects the light rays on the object side by arranging three mirror groups on the optical axis, wherein the first partial mirror group is used to improve the numerical aperture on the object side, the second partial mirror group is used to eliminate chromatic aberration, and the third partial mirror group is used to correct the chromatic aberration in the 400nm-1000nm waveband. In addition, by constraining the mutual relationship between the distance D from the object plane to the image side of the sixth mirror group, the focal length fobj of the microscope objective, and the numerical aperture NA on the object side of the microscope objective, the numerical aperture of the microscope objective can be as high as 0.325, the field number can be as high as 40, and the working distance can be as high as 34mm, which can meet the working requirements of the metallographic microscope or the biological fluorescence microscope for long working distance, large object side field of view, and large numerical aperture. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of the microscope objective in Example 1 provided by the present application;

[0026] Figure 2 is a 0 field lateral aberration diagram of the microscope objective in Example 1;

[0027] Figure 3 is a 1 field lateral aberration diagram of the microscope objective in Example 1;

[0028] Figure 4 is a field curvature distortion diagram of the microscope objective in Example 1;

[0029] Figure 5 is a chromatic aberration curve diagram of the microscope objective in Example 1;

[0030] Figure 6 is a structural schematic diagram of the microscope objective in Example 2 provided by the present application;

[0031] Figure 7 is a 0 field lateral aberration diagram of the microscope objective in Example 2;

[0032] Figure 8is a lateral aberration map of a 1 field of the microscope objective of Example 2;

[0033] Figure 9 is a field curvature distortion map of the microscope objective of Example 2;

[0034] Figure 10 is a lateral aberration map of a 1 field of the microscope objective of Example 2;

[0035] Figure 11 is a lateral aberration map of a 0 field of the microscope objective of Example 3;

[0036] Figure 12 is a lateral aberration map of a 1 field of the microscope objective of Example 3;

[0037] Figure 13 is a lateral aberration map of a 1 field of the microscope objective of Example 2;

[0038] Figure 14 is a field curvature distortion map of the microscope objective of Example 3;

[0039] Figure 15 is a lateral aberration map of a 1 field of the microscope objective of Example 2;

[0040] Reference Signs:

[0041] T1, first part mirror group; T2, second part mirror group; T3, third part mirror group; G1, first mirror group; G2, second mirror group; G3, third mirror group; G4, fourth mirror group; G5, fifth mirror group; G6, sixth mirror group; L1, first lens; L2, second lens; L3, third lens; L3a, third sub-lens; L3b, third sub-sub-lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; L11, eleventh lens. DETAILED DESCRIPTION

[0042] For a better understanding of the present application, various aspects of the present application will be described in greater detail below with reference to the accompanying drawings. It is to be understood that the detailed description is merely exemplary of the application and is not intended to limit the scope of the application in any way. Throughout the specification, like reference numerals refer to like elements in which:

[0043] It should be noted that the terms first, second, third, etc. are used herein only to distinguish one element from another, and do not denote any limitation. Thus, a first lens discussed below could also be termed a second lens or a third lens, without departing from the teachings of the present application.

[0044] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0045] In this context, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If the lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The judgment of the surface shape in the paraxial region can be made in accordance with the general method in the art, for example, judging convexity or concavity by the sign of the R value (R refers to the radius of curvature in the paraxial region). In this context, the surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the imaging surface is referred to as the image side surface of the lens. In terms of the object side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave. In terms of the image side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0046] It should also be understood that the use of the terms "including", "including have", "have", "contain" and / or "contain have", when used in this specification, indicates the presence of the stated features, elements and / or components, but does not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of" appear after a list of listed features, they modify the entire list of features and not the individual elements in the list. In addition, when describing embodiments of the present application, the use of "may" indicates "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0047] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0048] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The following embodiments only express several embodiments of the present application, which are described in detail and specifically, but can not be interpreted as a limitation on the scope of the patent of the present application. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] Please refer to Figure 1 , Figure 1 The structural schematic diagram of a microscope objective provided by one embodiment of the present application.

[0050] A microscope objective, comprising, arranged in order from object side to image side:

[0051] A first part lens group T1, comprising, arranged in order from object side to image side, a first lens group G1 and a second lens group G2, the focal power of the first lens group G1 being negative, and the focal power of the second lens group G2 being negative;

[0052] A second part lens group T2, comprising, arranged in order from object side to image side, a third lens group G3 and a fourth lens group G4, the focal power of the third lens group G3 being positive, and the focal power of the fourth lens group G4 being positive;

[0053] A third part lens group T3, comprising, arranged in order from object side to image side, a fifth lens group G5 and a sixth lens group G6, the focal power of the fifth lens group G5 being positive, and the focal power of the sixth lens group G6 being positive;

[0054] In particular, the microscope objective satisfies:

[0055] 4.5 < D / fobj < 4.6;

[0056] fobj > 20; and

[0057] 0.2 < NA < 0.325;

[0058] Wherein, D is the distance from the object plane to the image side of the sixth lens group G6; fobj is the focal length of the microscope objective; NA is the object side numerical aperture of the microscope objective.

[0059] It is worth noting that the microscope objective of the present application optimizes and corrects the light rays on the object side by arranging three mirror groups on the optical axis, wherein the first part of the mirror group T1 is used to improve the numerical aperture on the object side, the second part of the mirror group T2 is used to eliminate chromatic aberration, and the third part of the mirror group is used to correct the chromatic aberration of the 400nm-1000nm wave band. In addition, by constraining the mutual relationship between the distance D from the object plane to the image side of the sixth mirror group G6, the focal length fobj of the microscope objective, and the numerical aperture NA of the microscope objective, the numerical aperture of the microscope objective can reach up to 0.325, the field number can reach up to 40, and the working distance can reach up to 34mm, which can meet the working requirements of long working distance, large object side field of view and large numerical aperture of the microscope objective.

[0060] According to some embodiments of the present application, the first mirror group G1 includes a first lens L1 and a second lens L2 that are mutually cemented, the image side and the object side of the first lens L1 are both concave, and the object side of the second lens L2 is convex and the image side is concave.

[0061] The focal length fL1 of the first lens L1, the curvature radius RL1 of the image side of the first lens L1, and the focal length fobj of the microscope objective satisfy: 0.72≤|fL1 / fobj|≤0.74, 0.79≤|RL1 / fobj|≤0.99.

[0062] In this way, by correlating and constraining the focal length of the first lens L1, the curvature radius of the image side of the first lens L1, and the focal length of the microscope objective, it is ensured that the field of view range can be further increased on the basis of meeting the application requirements of the working distance of the microscope actual scene, which facilitates the observation personnel to obtain more sample information in the same picture, helps to quickly locate the position of the observation target, and improves the observation efficiency.

[0063] According to some embodiments of the present application, the second mirror group G2 includes a third sub-lens L3a and a third sub-lens L3b that are mutually cemented, the object side of the third sub-lens L3a is concave, the image side of the third sub-lens L3a is flat, the object side of the third sub-lens L3b is flat, and the image side of the third sub-lens L3b is convex.

[0064] In this way, unlike the embodiment of the second mirror group G2 including only a single lens L3, the embodiment of the second mirror group G2 containing double-cemented sub-lenses is more convenient for lens optical processing, which can effectively reduce the difficulty of objective lens assembly and calibration.

[0065] According to some embodiments of the present application, the third mirror group G3 comprises, in order from the object side to the image side, a fourth lens L4, a fifth lens L5 and a sixth lens L6, the object side surface of the fourth lens L4 is a plane and the image side surface is a convex surface, the object side surface and the image side surface of the fifth lens L5 are both concave surfaces, and the object side surface and the image side surface of the sixth lens L6 are both convex surfaces.

[0066] The fourth mirror group G4 comprises, in order from the object side to the image side, a seventh lens L7, an eighth lens L8 and a ninth lens L9, the object side surface and the image side surface of the seventh lens L7 are both convex surfaces, the object side surface and the image side surface of the eighth lens L8 are both concave surfaces, and the object side surface and the image side surface of the ninth lens L9 are both convex surfaces.

[0067] In this way, the second partial mirror group comprises two three-lens groups, the third mirror group G3 and the fourth mirror group G4, which can effectively correct the residual aberration of the objective lens and improve the imaging quality of the objective lens.

[0068] According to some embodiments of the present application, the fifth lens L5 and / or the eighth lens L8 are made of low-dispersion material.

[0069] In this way, the lens made of low-dispersion material with negative focal power can be matched with a lens made of high-dispersion material to effectively suppress the generation of chromatic aberration of the objective lens.

[0070] According to some embodiments of the present application, the fifth mirror group G5 comprises a tenth lens L10, the object side surface of the tenth lens L10 is a convex surface, and the image side surface of the tenth lens L10 is a plane, and the sixth mirror group G6 comprises an eleventh lens L11, the object side surface of the eleventh lens L11 is a convex surface, and the image side surface of the eleventh lens L11 is a concave surface.

[0071] In this way, by designing the surface shapes of the tenth lens L10 and the eleventh lens L11, the field curvature of the microscope objective lens is further corrected, and the field of view is also increased.

[0072] According to some embodiments of the present application, the minimum projection height H1 of the central field of view edge light in the lens surface in the third partial mirror group T3, the maximum projection height H2 of the central field of view edge light in the lens surface in the second partial mirror group T2, and the projection height H3 of the central field of view edge light in the lens surface closest to the image side in the first partial mirror group T1 satisfy: 0.92≤|H2 / H3|≤1.07; 1.79≤|H1 / H2|≤1.89.

[0073] In this way, the central field of view edge light within the range has a relatively flat light path, and the objective lens optical system is more easily corrected to ensure the imaging quality of the objective lens.

[0074] According to some embodiments of this application, the focal length fT1 of the first partial lens group T1 and the focal length fobj of the microscope objective lens satisfy the following condition: 1.46≤|fT1 / fobj|≤1.47.

[0075] According to some embodiments of this application, the focal length fT2 of the second part of the lens group T2 and the focal length fobj of the microscope objective lens satisfy the following condition: 3.52≤|fT2 / fobj|≤3.58.

[0076] According to some embodiments of this application, the focal length fT3 of the third lens group T3 and the focal length fobj of the microscope objective lens satisfy 1.68≤|fT3 / fobj|≤1.69.

[0077] In this way, by constraining the focal length of the three lens groups and the focal length of the microscope objective, it is beneficial to ensure the optical performance of the microscope objective provided in this application and improve the image quality.

[0078] The embodiments of the present invention are described in detail below, and examples of the invention are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0079] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0080] It is worth noting that, in the description of this invention, the microscope objective is an infinity conjugate objective.

[0081] The materials used in the following embodiments are for illustrative purposes only and should not be construed as limiting the invention to the materials used in these embodiments.

[0082] For ease of description, in the following embodiments, the working distance is the distance from the object surface of the sample to be observed to the object surface of the microscope objective, the numerical aperture NA represents the size of the receiving cone angle of the lens, Nd is the refractive index of the lens, and Vd is the dispersion coefficient of the lens material.

[0083] Example 1

[0084] like Figure 1 As shown, in this embodiment, the microscope objective consists of 3 lens groups, totaling 12 lenses. Specifically:

[0085] The first partial lens group T1 includes two cemented lens groups G1 and G2, the first lens group G1 includes a first lens L1 and a second lens L2 cemented with each other, wherein the object side surface of the first lens L1 is concave and the image side surface is concave, the object side surface of the second lens L2 is convex and the image side surface is concave, the second lens group G2 includes a third sub-lens L3a and a third sub-lens L3b cemented with each other, the object side surface of the third sub-lens L3a is concave and the image side surface is flat, the object side surface of the third sub-lens L3b is flat and the image side surface is convex;

[0086] The second partial lens group T2 includes two cemented lens groups G3 and G4, the third lens group G3 includes a fourth lens L4, a fifth lens L5 and a sixth lens L6 cemented with each other from the object side to the image side, wherein the object side surface of the fourth lens L4 is flat and the image side surface is convex, the object side surface of the fifth lens L5 is concave and the image side surface is concave, the object side surface of the sixth lens L6 is convex and the image side surface is convex, the fourth lens group G4 includes a seventh lens L7, an eighth lens L8 and a ninth lens L9 cemented with each other from the object side to the image side, wherein the object side surface of the seventh lens L7 is convex and the image side surface is convex, the object side surface of the eighth lens L8 is concave and the image side surface is concave, the object side surface of the ninth lens L9 is convex and the image side surface is convex;

[0087] The third partial lens group T3 includes two single lenses L10 and L11, wherein the object side surface of the tenth lens L10 is convex and the image side surface is flat, the object side surface of the eleventh lens L11 is convex and the image side surface is concave, and the eleventh lens L11 has positive refractive power.

[0088] Among the above three lens groups, the multiple lenses of the first partial lens group T1 provide refractive power, which is mainly used to increase the object side numerical aperture of the microscope objective to meet the demand of the existing microscope objective for large numerical aperture, so that the numerical apertures of the second partial lens group T2 and the third partial lens group T3 are reduced, in other words, when designing the second partial lens group T2 and the third partial lens group T3, only the requirements of correcting chromatic aberration, distortion and field curvature need to be considered, which facilitates the design and is also conducive to improving the correction effect of chromatic aberration, distortion and field curvature; the second partial lens group T2 is mainly used to correct chromatic aberration; the third partial lens group T3 provides refractive power and also provides a large field of view, which is mainly used to correct field curvature.

[0089] The working distance of the microscope objective provided in the embodiment is 34 mm, and the light propagation medium between the sample to be measured and the microscope objective is air.

[0090] The microscope objective provided in the embodiment is mainly used for metallographic microscopy, the spectral range of the microscope objective is 400 nm-700 nm, the field of view range is 36 mm, and the numerical aperture is 0.25. The microscope objective further includes the following features:

[0091] D / fobj = 4.56;

[0092] Fobj = 20;

[0093] NA = 0.25;

[0094] D represents the distance from the object plane to the last surface of the microscope objective; fobj represents the focal length of the microscope objective; and NA represents the numerical aperture of the microscope objective.

[0095] |H2 / H3| = 1.79;

[0096] |H1 / H2| = 0.92;

[0097] H1 represents the lowest surface projection height of the central field edge light in the first partial lens group T1; H2 represents the highest surface projection height of the central field edge light in the second partial lens group T2; and H3 represents the surface projection height of the central field edge light in the third partial lens group T3 closest to the image side.

[0098] |fL1 / fobj| = 0.72;

[0099] |RL1 / fobj| = 0.96;

[0100] fL1 represents the focal length of the first lens L1; RL1 represents the radius of curvature value of the image side of the first lens L1; and fobj represents the focal length of the microscope objective.

[0101] |fT1 / fobj| = 1.47;

[0102] wherein fT1 is the focal length of the first partial lens group T1, and fobj is the focal length of the microscope objective;

[0103] |fT2 / fobj| = 3.58;

[0104] wherein fT2 is the focal length of the second partial lens group T2, and fobj is the focal length of the microscope objective;

[0105] |fT3 / fobj| = 1.68;

[0106] wherein fT3 is the focal length of the third partial lens group T3, and fobj is the focal length of the microscope objective;

[0107] In this embodiment, the system focal length fobj is 20 mm, the working distance is 34 mm, the numerical aperture is 0.25, and the lens parameters of the microscope objective satisfy the conditions of Table 1:

[0108] Table 1 Lens optical parameters of the microscope objective in Example 1

[0109] In this embodiment, the system focal length fobj is 20 mm, the working distance is 34 mm, the numerical aperture is 0.25, and the lens parameters of the microscope objective satisfy the conditions of Table 1:

[0110]

[0111] Wherein, S1 is the object side surface of the first lens L1, S18 is the image side surface of the eleventh lens L11, and the thickness represents the on-axis distance from the current surface to the next surface. For example, the thickness of surface S1 is the distance from S1 to S2, which may be the on-axis thickness of the medium or lens, or it may be the on-axis air gap between them.

[0112] Figure 2 This is a lateral aberration diagram of the microscope objective lens in Example 1 at 0 field of view. The horizontal axis PY and PX represent the normalized entrance pupil size, the vertical axis represents the lateral aberration, the scale bar is ±5 micrometers, the Y direction is the meridional direction, and the X direction is the sagittal direction. As can be seen from the figure, the aberration balance is good, and it has good imaging performance.

[0113] Figure 3 This is a lateral aberration diagram of the first field of view of the microscope objective lens of Example 1, with a scale bar of ±5 micrometers. As can be seen from the figure, the curve is close to the horizontal axis, indicating good imaging performance.

[0114] Figure 4 The left image shows the field curvature and distortion of the microscope objective lens in Example 1. The vertical axis represents the field of view, and the horizontal axis represents the field curvature, both in μm. The axial difference between the optimal focusing point at the edge of the field of view and the optimal focusing point at the center of the field of view is small, ensuring sharpness across the entire field of view and meeting the requirements for a field-plan objective. The vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 5 μm and a minimum value of -5 μm. The right image shows the distortion, with the vertical axis representing the field of view and the horizontal axis representing the distortion (percentage). As shown in the image, the distortion across the entire field of view is less than 0.77%. The vertical axis represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 1% and a minimum of -1%.

[0115] Figure 5 This is the chromatic aberration curve of the microscope objective lens in Example 1, showing good chromatic aberration correction across the entire wavelength curve.

[0116] The microscope objective lens provided in this embodiment has a large field of view (36mm), which makes it convenient for users to obtain information about metal samples within a large field of view when used in metallographic microscopes.

[0117] Example 2

[0118] like Figure 6 As shown, in this embodiment, the microscope objective consists of 3 lens groups, totaling 12 lenses. The lens surface type and optical power in Embodiment 2 are the same as in Embodiment 1.

[0119] The working distance of the microscope objective provided in this embodiment is 34mm, and the light propagation medium between the sample to be tested and the microscope objective is air.

[0120] The microscope objective provided by the embodiment is mainly used for metallographic microscope, and the microscope objective further comprises the following features.

[0121] D / fobj=4.56;

[0122] Fobj=20;

[0123] NA=0.3;

[0124] D represents the distance from the object plane to the last surface of the microscope objective; fobj represents the focal length of the microscope objective; and NA represents the object-side numerical aperture of the microscope objective.

[0125] |H2 / H3|=1.89;

[0126] |H1 / H2|=1.01;

[0127] H1 represents the lowest surface projection height of the central field edge light in the first partial lens group T1; H2 represents the highest surface projection height of the central field edge light in the second partial lens group T2; and H3 represents the surface projection height of the central field edge light in the third partial lens group T3 closest to the image side.

[0128] |fL1 / fobj|=0.73;

[0129] |RL1 / fobj|=0.99;

[0130] fL1 represents the focal length of the first lens L1; RL1 represents the radius of curvature value of the image side of the first lens L1; and fobj represents the focal length of the microscope objective.

[0131] |fT1 / fobj|=1.46;

[0132] Wherein, fT1 is the focal length of the first partial lens group T1, and fobj is the focal length of the microscope objective.

[0133] |fT2 / fobj|=3.52;

[0134] Wherein, fT2 is the focal length of the second partial lens group T2, and fobj is the focal length of the microscope objective.

[0135] |fT3 / fobj|=1.69;

[0136] Wherein, fT3 is the focal length of the third partial lens group T3, and fobj is the focal length of the microscope objective.

[0137] In this embodiment, the system focal length fobj is 20 mm, the working distance is 34 mm, the numerical aperture is 0.3, the field of view range is 40 mm, and the lens parameters of the microscope objective meet the conditions of Table 2:

[0138] Table 2 Lens optical parameters of the microscope objective of Example 2

[0139] Surface Radius (mm) Thickness (mm) Nd Vd S1 -19.85 4.47 1.56 71.30 S2 15.5 2.65 1.80 34.97 S3 64.284 2.5 S4 -16.2 4.67 1.96 17.47 S5 Infinity 5 1.96 17.47 S6 -25.7 0.1 S7 Infinity 5.12 1.90 31.32 S8 -60.46 4 1.67 47.19 S9 50.731 5.65 1.49 81.61 S10 -28.77 0.1 S11 74.479 6.92 1.44 94.94 S12 -23.08 1.55 1.64 42.41 S13 28.44 5.45 1.44 94.94 S14 -81.1 0.1 S15 36.86 3.75 1.59 68.34 S16 Infinity 0.1 S17 25.7 4.12 1.44 94.94 S18 127.552 34.6

[0140] Wherein, S1 is the object side of the first lens L1, S18 is the image side of the eleventh lens L11, the thickness represents the axial distance from the current surface to the next surface, for example, the thickness of surface S1 is the distance from S1 to S2, which can be the axial thickness of the medium or lens, or the axial air gap between them.

[0141] Figure 7 is the 0 field of view lateral aberration chart of the microscope objective of Example 2, wherein the abscissa PY, PX represents the normalized entrance pupil size, the ordinate represents the lateral aberration, the scale is ± 10 microns, the Y direction is the meridional direction, and the X direction is the sagittal direction. As can be seen from the figure, the aberration is well balanced, and has good imaging performance.

[0142] Figure 8 is the 1 field of view lateral aberration chart of the microscope objective of Example 2, and the scale is ± 10 microns. As can be seen from the figure, the curve is close to the abscissa, and has good imaging performance.

[0143] Figure 9 is the field curvature distortion chart of the microscope objective of Example 2, the left figure is the field curvature chart, the ordinate represents the field of view, and the abscissa represents the field curvature, with units of microns. The axial difference between the best focus point of the edge field of view and the best focus point of the center field of view is small, and the theoretical value meets the clear full field of view requirement, reaching the flat field objective requirement. The ordinate in the figure is the normalized field of view; the abscissa represents the field curvature, with a maximum value of 10 microns and a minimum value of -10 microns. The right figure is the distortion chart, the ordinate represents the field of view, and the abscissa represents the distortion (percentage). As can be seen from the figure, the full field of view distortion is less than 1%. The ordinate in the figure is the normalized field of view, and the abscissa represents the distortion, with a maximum value of 1% and a minimum value of -1%.

[0144] Figure 10 is the chromatic aberration curve chart of the microscope objective of Example 1, and the full wavelength curve chromatic aberration correction is good.

[0145] The microscope objective provided in this embodiment has a large field of view (40 mm) and a large numerical aperture (NA = 0.3), and can be used in a metallographic microscope to facilitate the user to obtain metal sample information within a larger field of view range.

[0146] Example 3

[0147] As Figure 11As shown, in this embodiment, the microscope objective is composed of 3 mirror groups, and totally 11 lenses. Specifically:

[0148] The first partial mirror group T1 includes two cemented mirror groups G1 and G2, the first mirror group G1 includes a first lens L1 and a second lens L2 cemented with each other, wherein the object side surface of the first lens L1 is concave and the image side surface is concave, the object side surface of the second lens L2 is convex and the image side surface is concave, and the second mirror group G2 includes a third lens L3, wherein the object side surface of the third lens L3 is concave and the image side surface is convex;

[0149] The second partial mirror group T2 includes two cemented mirror groups G3 and G4, the third mirror group G3 includes a fourth lens L4, a fifth lens L5 and a sixth lens L6 cemented with each other from the object side to the image side, wherein the object side surface of the fourth lens L4 is flat and the image side surface is convex, the object side surface of the fifth lens L5 is concave and the image side surface is concave, and the object side surface of the sixth lens L6 is convex and the image side surface is convex, and the fourth mirror group G4 includes a seventh lens L7, an eighth lens L8 and a ninth lens L9 cemented with each other from the object side to the image side, wherein the object side surface of the seventh lens L7 is convex and the image side surface is convex, the object side surface of the eighth lens L8 is concave and the image side surface is concave, and the object side surface of the ninth lens L9 is convex and the image side surface is convex;

[0150] The third partial mirror group T3 includes two single lenses L10 and L11, wherein the object side surface of the tenth lens L10 is convex and the image side surface is flat, and the object side surface of the eleventh lens L11 is convex and the image side surface is concave, and the eleventh lens L11 has positive refractive power.

[0151] In the above three mirror groups, the multiple lenses of the first partial mirror group T1 provide refractive power, which is mainly used to increase the object side numerical aperture of the microscope objective to meet the requirement of the existing microscope objective for large numerical aperture, so that the numerical apertures of the second partial mirror group T2 and the third partial mirror group T3 are reduced, in other words, when designing the second partial mirror group T2 and the third partial mirror group T3, only the requirements of correcting chromatic aberration, distortion and field curvature need to be considered, which facilitates the design and is also conducive to improving the correction effect of chromatic aberration, distortion and field curvature; the second partial mirror group T2 is mainly used to correct chromatic aberration; the third partial mirror group T3 provides refractive power and also provides a large field of view, which is mainly used to correct field curvature.

[0152] In this embodiment, the fourth lens L4 in the third mirror group G3 can be made of low dispersion material and the sixth lens L6 can be made of high dispersion material, which can further optimize the chromatic aberration of the entire microscope objective and ensure that the image side picture of the microscope objective is more realistic.

[0153] The working distance of the microscope objective provided in this embodiment is 34 mm, and the light propagation medium between the sample to be measured and the microscope objective is air.

[0154] The microscope objective provided by the embodiment is mainly used for biological fluorescence microscopy, and the microscope objective further comprises the following features.

[0155] D / fobj=4.57;

[0156] Fobj=20.1;

[0157] NA=0.325;

[0158] D represents the distance from the object plane to the last surface of the microscope objective; fobj represents the focal length of the microscope objective; and NA represents the object-side numerical aperture of the microscope objective.

[0159] |H2 / H3|=1.87;

[0160] |H1 / H2|=1.07;

[0161] H1 represents the lowest surface projection height of the central field edge light in the first partial lens group T1; H2 represents the highest surface projection height of the central field edge light in the second partial lens group T2; and H3 represents the surface projection height of the central field edge light in the third partial lens group T3 closest to the image side.

[0162] |fL1 / fobj|=0.74;

[0163] |RL1 / fobj|=0.79;

[0164] fL1 represents the focal length of the first lens L1; RL1 represents the radius of curvature value of the image side of the first lens L1; and fobj represents the focal length of the microscope objective.

[0165] |fT1 / fobj|=1.47;

[0166] wherein fT1 is the focal length of the first partial lens group T1, and fobj is the focal length of the microscope objective;

[0167] |fT2 / fobj|=3.56;

[0168] wherein fT2 is the focal length of the second partial lens group T2, and fobj is the focal length of the microscope objective;

[0169] |fT3 / fobj|=1.68;

[0170] wherein fT3 is the focal length of the third partial lens group T3, and fobj is the focal length of the microscope objective;

[0171] In this embodiment, the system focal length fobj is 20.1 mm, the working distance is 34 mm, the numerical aperture is 0.325, the field of view range is 40 mm, and the lens parameters of the microscope objective meet the conditions of Table 3:

[0172] Table 3 Lens optical parameters of the microscope objective of Example 3

[0173] Surface Radius (mm) Thickness (mm) Nd Vd S1 -19.91 4.47 1.56 71.30 S2 15.778 2.65 1.80 34.97 S3 65.876 2.5 S4 -16.208 9.67 1.96 17.47 S5 -25.639 0.1 S6 Infinity 5.12 1.90 31.32 S7 -60.752 4 1.67 47.19 S8 51.522 5.65 1.49 81.61 S9 -28.781 0.1 S10 76.928 6.92 1.44 94.94 S11 -23.301 1.55 1.64 42.41 S12 27.983 5.45 1.44 94.94 S13 -81.885 0.1 S14 36.769 3.75 1.59 68.34 S15 Infinity 0.1 S16 25.639 4.12 1.44 94.94 S17 129.691 34.7

[0174] Wherein, S1 is the object side of the first lens L1, S17 is the image side of the eleventh lens L11, the thickness represents the axial distance from the current surface to the next surface, for example, the thickness of surface S1 is the distance from S1 to S2, which can be the axial thickness of the medium or lens, or the axial air gap between them.

[0175] Figure 12 is the 0 field of view lateral aberration diagram of the microscope objective of Example 2, wherein the abscissa PY, PX represents the normalized entrance pupil size, the ordinate represents the lateral aberration, the scale is ± 10 microns, the Y direction is the meridional direction, and the X direction is the sagittal direction. As can be seen from the figure, the aberration is well balanced, and has good imaging performance.

[0176] Figure 13 is the 1 field of view lateral aberration diagram of the microscope objective of Example 2, and the scale is ± 10 microns. As can be seen from the figure, the curve is close to the abscissa, and has good imaging performance.

[0177] Figure 14 is the field curvature distortion diagram of the microscope objective of Example 2, the left figure is the field curvature diagram, the ordinate represents the field of view, and the abscissa represents the field curvature, with units of microns. The axial difference between the best focus point of the edge field of view and the best focus point of the center field of view is small, and the theoretical value meets the clear full field of view requirement, meeting the flat field objective requirement. The ordinate in the figure is the normalized field of view, and the abscissa represents the field curvature, with a maximum value of 10 microns and a minimum value of -10 microns. The right figure is a distortion diagram, wherein the ordinate represents the field of view, and the abscissa represents the distortion (percentage). As can be seen from the figure, the full field of view distortion is less than 1%. The ordinate in the figure is the normalized field of view, and the abscissa represents the distortion, with a maximum value of 1% and a minimum value of -1%.

[0178] Figure 15 is the chromatic aberration curve diagram of the microscope objective of Example 1, and the full wavelength curve chromatic aberration correction is good.

[0179] The microscope objective provided in this embodiment has a large field of view (40 mm) and a large numerical aperture (NA = 0.325), and can be used in a biological fluorescence microscope to facilitate the user to obtain biological sample information within a larger field of view range.

[0180] Optionally, in some embodiments, the working wavelength range of the microscope objective can be 436nm-1000nm, preferably, the imaging effect is best in the wavelength range of 436nm-656nm.

[0181] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0182] The above-mentioned embodiments only express several embodiments of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A microscope objective, characterized in that The microscope objective comprises, arranged in order from the object side to the image side: a first partial lens group comprising a first lens group and a second lens group arranged in order from the object side to the image side, the first lens group having a negative refractive power, and the second lens group having a negative refractive power; the first lens group comprising a first lens and a second lens cemented to each other, the object side surface and the image side surface of the first lens being concave, and the object side surface of the second lens being convex and the image side surface of the second lens being concave; the object side surface of the second lens group being concave and the image side surface of the second lens group being convex; a second partial lens group comprising a third lens group and a fourth lens group arranged in order from the object side to the image side, the third lens group having a positive refractive power, and the fourth lens group having a positive refractive power; the third lens group comprising a fourth lens, a fifth lens and a sixth lens cemented to each other in order from the object side to the image side, the object side surface of the fourth lens being a plane and the image side surface of the fourth lens being convex, the object side surface and the image side surface of the fifth lens being concave, and the object side surface and the image side surface of the sixth lens being convex; the fourth lens group comprising a seventh lens, an eighth lens and a ninth lens cemented to each other in order from the object side to the image side, the object side surface and the image side surface of the seventh lens being convex, the object side surface and the image side surface of the eighth lens being concave, and the object side surface and the image side surface of the ninth lens being convex; a third partial lens group comprising a fifth lens group and a sixth lens group arranged in order from the object side to the image side, the fifth lens group having a positive refractive power, and the sixth lens group having a positive refractive power; the fifth lens group comprising a tenth lens, the object side surface of the tenth lens being convex, and the image side surface of the tenth lens being a plane; the sixth lens group comprising an eleventh lens, the object side surface of the eleventh lens being convex, and the image side surface of the eleventh lens being concave; the microscope objective satisfying: 4.5 < D / fobj < 4.6, fobj > 20, and 0.2 < NA ≤ 0.325, wherein D is the distance from the object plane to the image side surface of the sixth lens group, fobj is the focal length of the microscope objective, and NA is the object side numerical aperture of the microscope objective.

2. The microscope objective according to claim 1, characterized in that the focal length of the first lens fL1, the radius of curvature of the image side surface of the first lens RL1, and the focal length of the microscope objective fobj satisfying: 0.72 ≤ |fL1 / fobj| ≤ 0.74, and 0.79 ≤ |RL1 / fobj| ≤ 0.

99.

3. The microscope objective according to claim 2, characterized in that the second lens group comprising a third sub-lens and a third tertiary sub-lens cemented to each other, the object side surface of the third sub-lens being concave, the image side surface of the third sub-lens being a plane, the object side surface of the third tertiary sub-lens being a plane, and the image side surface of the third tertiary sub-lens being convex.

4. The microscope objective according to claim 1, characterized in that the fifth lens and / or the eighth lens being made of a low dispersion material.

5. The microscope objective according to any one of claims 1 to 4, characterized in that the minimum projection height H1 of the central field of view edge light in the lens surface of the third partial lens group, the maximum projection height H2 of the central field of view edge light in the lens surface of the second partial lens group, and the projection height H3 of the central field of view edge light in the lens surface closest to the image side in the first partial lens group satisfying: 0.92 < |H2 / H3| < 1.07, and 1.79 < |H1 / H2| < 1.

89.

6. The microscope objective according to any one of claims 1 to 4, characterized in that The focal length fT1 of the first partial mirror group and the focal length fobj of the microscope objective satisfy: 1.45≤|fT1 / fobj|≤1.

48.

7. The microscope objective according to any one of claims 1 to 4, characterized in that The focal length fT2 of the second partial mirror group and the focal length fobj of the microscope objective satisfy: 3.52≤|fT2 / fobj|≤3.

58.

8. The microscope objective according to any one of claims 1 to 4, characterized in that The focal length fT3 of the third partial mirror group and the focal length fobj of the microscope objective satisfy: 1.68≤|fT3 / fobj|≤1.69.

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