Microscope objective lens

Abstract

The invention relates to a microscope objective lens, which comprises three lens groups which are sequentially arranged from an object space to an image space, the first lens group comprises a first lens group and a second lens group which are sequentially arranged from the object space to the image space, the focal power of the first lens group is negative, and the focal power of the second lens group is negative; the second part of lens group comprises a third lens group and a fourth lens group which are sequentially arranged from the object to the image, the focal power of the third lens group is positive, and the focal power of the fourth lens group is positive; the third part of lens group comprises a fifth lens group and a sixth lens group which are sequentially arranged from the object to the image, the focal power of the fifth lens group is positive, and the focal power of the sixth lens group is positive; the microscope objective lens satisfies: 3lt; d / fobjlt; 5, carrying out fobjgt; 15, 0.2 lt; nAlt; 0.3 part; 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 lens; nA is the object space numerical aperture of the microscope objective lens. The microscope objective lens has a large field of view, a large numerical aperture and good image quality.

Description

Technical Field

[0001] The present invention relates to the technical field of microscope objective lenses, and in particular to a microscope objective lens. Background Art

[0002] Due to the increasing requirements for observation resolution and imaging speed in the fields of life sciences and industry, the trend of microscope objectives is towards larger fields of view and larger numerical apertures (NA). While achieving large numerical aperture apochromatism, it is also necessary to ensure that the microscope objective has a long working distance and the structure has good machinability, which plays an important role in the production of large numerical aperture and ultra-long working distance microscope objectives, especially in the special use scenarios of metallographic microscopes and biological microscopes, where the demand for such microscope objectives is increasing. Summary of the invention

[0003] Since existing microscope objective lenses are difficult to achieve large numerical aperture apochromatism while ensuring that the microscope objective lenses have a long working distance, it is necessary to provide a microscope objective lens.

[0004] A microscope objective lens, comprising:

[0005] A first partial lens group includes a first lens group and a second lens group arranged in sequence from the object side to the image side, wherein the optical focal power of the first lens group is negative, and the optical focal power of the second lens group is negative;

[0006] The second partial lens group includes a third lens group and a fourth lens group arranged in sequence from the object side to the image side, the third lens group has a positive focal power, and the fourth lens group has a positive focal power;

[0007] The third partial lens group includes a fifth lens group and a sixth lens group arranged in sequence from the object side to the image side, the optical focal power of the fifth lens group is positive, and the optical focal power of the sixth lens group is positive;

[0008] In particular, the microscope objective meets the following requirements:

[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 surface of the sixth lens group; fobj is the focal length of the microscope objective lens; and NA is the object-side numerical aperture of the microscope objective lens.

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

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

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

[0016] In some embodiments of the present application, the third lens group includes a fourth lens, a fifth lens, and a sixth lens cemented in sequence from the object side to the image side, the object side surface of the fourth lens is a flat surface and the image side surface is a convex surface, the object side surface and the image side surface of the fifth lens are both concave surfaces, and the object side surface and the image side surface of the sixth lens are both convex surfaces;

[0017] The fourth lens group includes a seventh lens, an eighth lens, and a ninth lens cemented in sequence from the object side to the image side. The object side surface and the image side surface of the seventh lens are both convex surfaces, the object side surface and the image side surface of the eighth lens are both concave surfaces, and the object side surface and the image side surface of the ninth lens are both convex surfaces.

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

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

[0020] In some embodiments of the present application, the lowest projection height H1 of the edge light of the central field of view on the lens surface in the third partial mirror group, the highest projection height H2 of the edge light of the central field of view on the lens surface in the second partial mirror group, and the projection height H3 of the edge light of the central field of view on the surface of the lens closest to the image side in the first partial mirror group satisfy the following: 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 lens assembly and the focal length fobj of the microscope objective lens satisfy the following relationship: 1.45≤|fT1 / fobj|≤1.48.

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

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

[0024] In summary, the microscope objective of the present application optimizes and corrects the light on the object side by arranging three mirror groups on the optical axis, wherein the first mirror group is used to improve the object numerical aperture, the second mirror group is used to eliminate chromatic aberration, and the third mirror group is used to correct chromatic aberration in the 400nm~1000nm band. In addition, by constraining 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 object numerical aperture NA of the microscope objective, the numerical aperture of the microscope objective can reach up to 0.325, the field of view number can reach 40, and the working distance can reach 34mm, which can meet the working requirements of metallographic microscopes or biological fluorescence microscopes for long working distances, large object fields of view and large numerical apertures. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0026] Figure 2 is a lateral aberration diagram of the zero field of view of the microscope objective lens of Example 1;

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

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

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

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

[0031] Figure 7 is a lateral aberration diagram of the zero field of view of the microscope objective lens of Example 2;

[0032] Figure 8is a lateral aberration diagram of one field of view of the microscope objective lens of Example 2;

[0033] Fig. 9 is a field curvature distortion diagram of the microscope objective lens of Example 2;

[0034] Fig.10 is a chromatic aberration curve diagram of the microscope objective lens of Example 2;

[0035] Fig.11 is a schematic structural diagram of the microscope objective lens in Example 3 provided in the present application;

[0036] Fig.12 is a lateral aberration diagram of the zero field of view of the microscope objective lens of Example 3;

[0037] Fig.13 is a lateral aberration diagram of one field of view of the microscope objective lens of Example 3;

[0038] Fig.14 is a field curvature distortion diagram of the microscope objective lens of Example 3;

[0039] Fig.15 It is a chromatic aberration curve diagram of the microscope objective lens of Example 3.

[0040] Reference numerals:

[0041] T1, first partial mirror group; T2, second partial mirror group; T3, third partial 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-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] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

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

[0045] In this article, the paraxial area refers to the area near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial area; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial area. The judgment of the surface type in the paraxial area can be judged according to the general method in this field, for example, the positive and negative R value (R refers to the radius of curvature of the paraxial area) is used to judge the concave and convex. In this article, the surface of each lens closest to the subject is called the object side of the lens, and the surface of each lens closest to the imaging surface is called the image side of the lens. For the object side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface.

[0046] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do 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 listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "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 terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0048] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0049] See also Figure 1 , Figure 1 A schematic diagram of the structure of a microscope objective lens in an embodiment provided by the present invention.

[0050] A microscope objective lens, comprising:

[0051] A first partial lens group T1 includes a first lens group G1 and a second lens group G2 arranged in sequence from the object side to the image side, wherein the optical power of the first lens group G1 is negative, and the optical power of the second lens group G2 is negative;

[0052] The second partial lens group T2 includes a third lens group G3 and a fourth lens group G4 arranged in sequence from the object side to the image side, the third lens group G3 has a positive focal power, and the fourth lens group G4 has a positive focal power;

[0053] The third partial lens group T3 includes a fifth lens group G5 and a sixth lens group G6 arranged in sequence from the object side to the image side, the optical focal power of the fifth lens group G5 is positive, and the optical focal power of the sixth lens group G6 is positive;

[0054] In particular, the microscope objective meets the following requirements:

[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 surface of the sixth lens group G6; fobj is the focal length of the microscope objective lens; and NA is the object-side numerical aperture of the microscope objective lens.

[0059] It is worth noting that the microscope objective of the present application optimizes and corrects the light on the object side by arranging three mirror groups on the optical axis, wherein the first mirror group T1 is used to improve the object numerical aperture, the second mirror group T2 is used to eliminate chromatic aberration, and the third mirror group is used to correct chromatic aberration in the 400nm~1000nm band. In addition, by constraining 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 object numerical aperture NA of the microscope objective, the numerical aperture of the microscope objective can reach up to 0.325, the field of view number can reach 40, and the working distance can reach 34mm, which can meet the working requirements of the microscope objective with long working distance, large object field of view and large numerical aperture.

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

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

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

[0063] According to some embodiments of the present application, the second lens group G2 includes a third sub-lens L3a and a third sub-lens L3b that are glued to each other, the object side surface of the third sub-lens L3a is a concave surface, the image side surface of the third sub-lens L3a is a plane, the object side surface of the third sub-lens L3b is a plane, and the image side surface of the third sub-lens L3b is a convex surface.

[0064] Thus, different from the embodiment of the second lens group G2 including only the single lens L3, the embodiment of the second lens group G2 including the double-cemented sub-lens is more convenient for lens optical processing and can effectively reduce the difficulty of objective lens assembly and calibration.

[0065] According to some embodiments of the present application, the third lens group G3 includes a fourth lens L4, a fifth lens L5, and a sixth lens L6 that are cemented in order from the object side to the image side, the object-side surface of the fourth lens L4 is a flat surface 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 lens group G4 includes a seventh lens L7, an eighth lens L8, and a ninth lens L9 cemented in order from the object side to the image side. 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 lens group includes two triple-cemented lens groups, namely the third lens group G3 and the fourth lens group G4, which can effectively correct the residual aberration of the objective lens and improve the image 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 materials.

[0069] In this way, a lens made of a low-dispersion material with negative optical power can be matched with a lens made of a 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 lens group G5 includes 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; the sixth lens group G6 includes 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 can also be increased.

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

[0073] In this way, the light at the edge of the central field of view within this range has a relatively gentle light trend, and the objective optical system is easier to correct aberrations to ensure the imaging quality of the objective;

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

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

[0076] According to some embodiments of the present application, the focal length fT3 of the third partial lens assembly 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-part lens assembly and the focal length of the microscope objective, it is helpful to ensure the optical performance of the microscope objective provided by the present application and improve the image quality.

[0078] 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.

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

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

[0081] The materials used in the following examples are for illustration only, and it should not be considered that the present invention is limited to the materials in these examples.

[0082] For ease of description, in the following embodiments, the working distance is the distance from the object plane of the sample to be observed to the object side surface of the microscope objective, the numerical aperture NA represents the size of the cone angle of light received by 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 lens is composed of 3 lens groups, a total of 12 lenses. Specifically:

[0085] The first 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 that are cemented together. 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 lens group G2 includes a third sub-lens L3a and a third sub-lens L3b that are cemented together. The object side surface of the third sub-lens L3a is concave and the image side surface is flat, and the object side surface of the third sub-lens L3b is flat and the image side surface is convex;

[0086] The second 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 which are cemented in sequence from the object side to the image side. The object side surface of the fourth lens L4 is a plane surface and the image side surface is a convex surface. The object side surface of the fifth lens L5 is a concave surface and the image side surface is a concave surface. The object side surface of the sixth lens L6 is a convex surface and the image side surface is a convex surface. The fourth lens group G4 includes a seventh lens L7, an eighth lens L8 and a ninth lens L9 which are cemented in sequence from the object side to the image side. The object side surface of the seventh lens L7 is a convex surface and the image side surface is a convex surface. The object side surface of the eighth lens L8 is a concave surface and the image side surface is a concave surface. The object side surface of the ninth lens L9 is a convex surface and the image side surface is a convex surface.

[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 optical power of the eleventh lens L11 is positive.

[0088] In the above three lens groups, the multiple lenses of the first partial lens group T1 provide optical focal length, which is mainly used to increase the object-side numerical aperture of the microscope objective to meet the demand for a large numerical aperture of the existing microscope objective, so that the numerical apertures of the second partial lens group T2 and the third partial lens group T3 can be reduced. In other words, when designing the second partial lens group T2 and the third partial lens group T3, it is only necessary to consider the demand for correcting chromatic aberration, distortion and field curvature, which facilitates the design and is also beneficial 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 can provide optical focal length and a large field of view at the same time, and is mainly used to correct field curvature.

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

[0090] The microscope objective lens provided in this embodiment is mainly used for metallographic microscopes. The spectral range of the microscope objective lens is 400nm to 700nm, the field of view is 36mm, and the numerical aperture is 0.25. The microscope objective lens also 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 side of the microscope objective; fobj represents the focal length of the microscope objective; NA represents the object side numerical aperture of the microscope objective.

[0095] |H2 / H3|=1.79;

[0096] |H1 / H2|=0.92;

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

[0098] |fL1 / fobj|=0.72;

[0099] |RL1 / fobj|=0.96;

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

[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 lens;

[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 lens;

[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 lens;

[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 lens meet the conditions of Table 1:

[0108] Table 1 Optical parameters of the lens of the microscope objective lens of Example 1

[0109]

[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 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 the on-axis air gap therebetween.

[0112] Figure 2 This is the lateral aberration diagram of the zero field of view of the microscope objective of Example 1, wherein the abscissas PY and PX represent the normalized entrance pupil size, the ordinate represents the lateral aberration, the scale is ±5 microns, the Y direction is the meridian direction, and the X direction is the sagittal direction. It can be seen from the figure that the aberration balance is good and has good imaging performance.

[0113] Figure 3 This is a lateral aberration diagram of the field of view of the microscope objective lens of Example 1, with a scale of ±5 microns. It can be seen from the figure that the curve is close to the horizontal axis and has good imaging performance.

[0114] Figure 4 This is the field curvature distortion diagram of the microscope objective lens of Example 1. The left figure is the field curvature diagram. The ordinate in the figure represents the field of view, and the abscissa represents the field curvature, with the unit being μm. The axial difference between the best focusing point of the edge field of view and the best focusing point of the center field of view is small, which satisfies the clarity of the entire field of view and meets the requirements of a flat-field objective lens. The ordinate in the figure is the normalized field of view; the abscissa represents the field curvature, with a maximum value of 5μm and a minimum value of -5μm. The right figure is the distortion diagram, in which the ordinate represents the field of view, and the abscissa represents the distortion (percentage). It can be seen from the figure that the distortion of the entire field of view is less than 0.77%. The ordinate in the figure is the normalized field of view, and the abscissa represents the distortion, with a maximum of 1% and a minimum of -1%.

[0115] Figure 5 It is a chromatic aberration curve diagram of the microscope objective lens of Example 1, and the full wavelength curve chromatic aberration correction is better.

[0116] The microscope objective lens provided in this embodiment has a large field of view (36 mm), and when used in a metallographic microscope, it is convenient for the user to obtain metal sample information within a larger field of view.

[0117] Example 2

[0118] like Figure 6 As shown, in this embodiment, the microscope objective lens is composed of 3 lens groups, a total of 12 lenses. The lens surface shape and optical focal length in embodiment 2 are the same as those in embodiment 1.

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

[0120] The microscope objective lens provided in this embodiment is mainly used for metallographic microscope, and the microscope objective lens also includes 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 side of the microscope objective; fobj represents the focal length of the microscope objective; 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 projection height of the edge light of the central field of view on the lens surface in the first partial lens group T1; H2 represents the highest projection height of the edge light of the central field of view on the lens surface in the second partial lens group T2; H3 represents the projection height of the edge light of the central field of view on the surface of the lens closest to the image side in the third partial lens group T3.

[0128] |fL1 / fobj|=0.73;

[0129] |RL1 / fobj|=0.99;

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

[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 lens;

[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 lens;

[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 lens;

[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 is 40 mm, and the lens parameters of the microscope objective lens meet the conditions of Table 2:

[0138] Table 2 Optical parameters of the lens of the microscope objective lens 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 surface of the first lens L1, S18 is the image-side surface of the eleventh lens L11, and 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 the on-axis air gap therebetween.

[0141] Figure 7 This is the lateral aberration diagram of the zero field of view of the microscope objective of Example 2, wherein the abscissas PY and PX represent the normalized entrance pupil size, the ordinate represents the lateral aberration, the scale is ±10 microns, the Y direction is the meridian direction, and the X direction is the sagittal direction. It can be seen from the figure that the aberration balance is good and has good imaging performance.

[0142] Figure 8 This is a lateral aberration diagram of the field of view of the microscope objective lens of Example 2, with a scale of ±10 microns. It can be seen from the figure that the curve is close to the horizontal axis and has good imaging performance.

[0143] Fig. 9 This is the field curvature distortion diagram of the microscope objective lens of Example 2. The left figure is the field curvature diagram. The ordinate in the figure represents the field of view, and the abscissa represents the field curvature, with the unit being μm. The axial difference between the best focusing point of the edge field of view and the best focusing point of the center field of view is small, and the theoretical value satisfies the clarity of the entire field of view and meets the requirements of a flat-field objective lens. The ordinate in the figure is the normalized field of view; the abscissa represents the field curvature, with a maximum value of 10μm and a minimum value of -10μm. The right figure is the distortion diagram, in which the ordinate represents the field of view, and the abscissa represents the distortion (percentage). It can be seen from the figure that the distortion of the entire field of view is less than 1%. The ordinate in the figure is the normalized field of view, and the abscissa represents the distortion, with a maximum of 1% and a minimum of -1%.

[0144] Fig.10 It is a chromatic aberration curve diagram of the microscope objective lens of Example 1, and the full wavelength curve chromatic aberration correction is better.

[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 users to obtain metal sample information within a larger field of view.

[0146] Example 3

[0147] like Fig.11As shown, in this embodiment, the microscope objective lens is composed of 3 lens groups, a total of 11 lenses. Specifically:

[0148] The first 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 that are cemented together. 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 lens L3. The object side surface of the third lens L3 is concave and the image side surface is convex.

[0149] The second 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 which are cemented in sequence from the object side to the image side. The object side surface of the fourth lens L4 is a plane surface and the image side surface is a convex surface. The object side surface of the fifth lens L5 is a concave surface and the image side surface is a concave surface. The object side surface of the sixth lens L6 is a convex surface and the image side surface is a convex surface. The fourth lens group G4 includes a seventh lens L7, an eighth lens L8 and a ninth lens L9 which are cemented in sequence from the object side to the image side. The object side surface of the seventh lens L7 is a convex surface and the image side surface is a convex surface. The object side surface of the eighth lens L8 is a concave surface and the image side surface is a concave surface. The object side surface of the ninth lens L9 is a convex surface and the image side surface is a convex surface.

[0150] 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 optical power of the eleventh lens L11 is positive.

[0151] In the above three lens groups, the multiple lenses of the first partial lens group T1 provide optical focal length, which is mainly used to increase the object-side numerical aperture of the microscope objective to meet the demand for a large numerical aperture of the existing microscope objective, so that the numerical apertures of the second partial lens group T2 and the third partial lens group T3 can be reduced. In other words, when designing the second partial lens group T2 and the third partial lens group T3, it is only necessary to consider the demand for correcting chromatic aberration, distortion and field curvature, which facilitates the design and is also beneficial 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 can provide optical focal length and a large field of view at the same time, and is mainly used to correct field curvature.

[0152] In this embodiment, the fourth lens L4 in the third lens 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 lens and ensure that the image side image of the microscope objective lens 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 tested and the microscope objective is air.

[0154] The microscope objective lens provided in this embodiment is mainly used for biological fluorescence microscopy, and the microscope objective lens also includes 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 side of the microscope objective; fobj represents the focal length of the microscope objective; 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 projection height of the edge light of the central field of view on the lens surface in the first partial lens group T1; H2 represents the highest projection height of the edge light of the central field of view on the lens surface in the second partial lens group T2; H3 represents the projection height of the edge light of the central field of view on the surface of the lens closest to the image side in the third partial lens group T3.

[0162] |fL1 / fobj|=0.74;

[0163] |RL1 / fobj|=0.79;

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

[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 lens;

[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 lens;

[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 lens;

[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 is 40 mm, and the lens parameters of the microscope objective lens meet the conditions of Table 3:

[0172] Table 3 Optical parameters of the lens of the microscope objective lens 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 surface of the first lens L1, S17 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 the surface S1 is the distance from S1 to S2, which may be the on-axis thickness of the medium or lens, or the on-axis air gap therebetween.

[0175] Fig.12 This is the lateral aberration diagram of the zero field of view of the microscope objective of Example 2, wherein the abscissas PY and PX represent the normalized entrance pupil size, the ordinate represents the lateral aberration, the scale is ±10 microns, the Y direction is the meridian direction, and the X direction is the sagittal direction. It can be seen from the figure that the aberration balance is good and has good imaging performance.

[0176] Fig.13 This is a lateral aberration diagram of the field of view of the microscope objective lens of Example 2, with a scale of ±10 microns. It can be seen from the figure that the curve is close to the horizontal axis and has good imaging performance.

[0177] Fig.14 This is the field curvature distortion diagram of the microscope objective lens of Example 2. The left figure is the field curvature diagram. The ordinate in the figure represents the field of view, and the abscissa represents the field curvature, with the unit being μm. The axial difference between the best focusing point of the edge field of view and the best focusing point of the center field of view is small, and the theoretical value satisfies the clarity of the entire field of view and meets the requirements of a flat-field objective lens. The ordinate in the figure is the normalized field of view; the abscissa represents the field curvature, with a maximum value of 10μm and a minimum value of -10μm. The right figure is the distortion diagram, in which the ordinate represents the field of view, and the abscissa represents the distortion (percentage). It can be seen from the figure that the distortion of the entire field of view is less than 1%. The ordinate in the figure is the normalized field of view, and the abscissa represents the distortion, with a maximum of 1% and a minimum of -1%.

[0178] Fig.15 It is a chromatic aberration curve diagram of the microscope objective lens of Example 1, and the full wavelength curve chromatic aberration correction is better.

[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 users to obtain biological sample information within a larger field of view.

[0180] Optionally, in some embodiments, the operating wavelength band of the microscope objective lens may be 436 nm to 1000 nm, and preferably, the imaging effect is best in the wavelength band range of 436 nm to 656 nm.

[0181] 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.

[0182] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A microscope objective lens, characterized in that: Including the following components arranged in sequence from the object side to the image side: The first part lens group, including a first lens group and a second lens group arranged in sequence from the object side to the image side, the optical power of the first lens group being negative and the optical power of the second lens group being negative; The second part lens group, including a third lens group and a fourth lens group arranged in sequence from the object side to the image side, the optical power of the third lens group being positive and the optical power of the fourth lens group being positive; The third part lens group, including a fifth lens group and a sixth lens group arranged in sequence from the object side to the image side, the optical power of the fifth lens group being positive and the optical power of the sixth lens group being positive; In particular, the microscope objective satisfies: 4.5 < D / fobj < 4.6, fobj > 20, 0.2 < NA ≤ 0.325, where 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 lens according to claim 1, characterized in that: The first lens group includes a first lens and a second lens that are cemented together. The object side surface and the image side surface of the first lens are both concave surfaces, and the object side surface of the second lens is a convex surface while the image side surface is a concave surface; The relationship among the focal length fL1 of the first lens, the curvature radius RL1 of the image side surface of the first lens, and the focal length fobj of the microscope objective satisfies: 0.72 ≤ |fL1 / fobj| ≤ 0.74, 0.79 ≤ |RL1 / fobj| ≤ 0.

99.

3. The microscope objective lens according to claim 2, characterized in that: The second lens group includes a third sub-lens and a third sub-lens that are cemented together. The object side surface of the third sub-lens is a concave surface, the image side surface of the third sub-lens is a flat surface, the object side surface of the third sub-lens is a flat surface, and the image side surface of the third sub-lens is a convex surface.

4. The microscope objective lens according to claim 1, characterized in that: The third lens group includes a fourth lens, a fifth lens, and a sixth lens that are cemented together in sequence from the object side to the image side. The object side surface of the fourth lens is a flat surface while the image side surface is a convex surface, the object side surface and the image side surface of the fifth lens are both concave surfaces, and the object side surface and the image side surface of the sixth lens are both convex surfaces; The fourth lens group includes a seventh lens, an eighth lens, and a ninth lens that are cemented together in sequence from the object side to the image side. The object side surface and the image side surface of the seventh lens are both convex surfaces, the object side surface and the image side surface of the eighth lens are both concave surfaces, and the object side surface and the image side surface of the ninth lens are both convex surfaces.

5. The microscope objective lens according to claim 4, characterized in that: The fifth lens and / or the eighth lens is / are made of a low-dispersion material.

6. The microscope objective lens according to claim 1, characterized in that: The fifth lens group includes a tenth lens. The object side surface of the tenth lens is a convex surface and the image side surface is a flat surface; the sixth lens group includes an eleventh lens. The object side surface of the eleventh lens is a convex surface and the image side surface is a concave surface.

7. The microscope objective according to any one of claims 1 to 6, characterized in that: The relationship among the lowest projection height H1 of the marginal ray of the central field of view on the lens surface in the third part lens group, the highest projection height H2 of the marginal ray of the central field of view on the lens surface in the second part lens group, and the projection height H3 of the marginal ray of the central field of view on the lens surface of the lens closest to the image side in the first part lens group satisfies: 0.92 < |H2 / H3| < 1.07, 1.79 < |H1 / H2| < 1.

89.

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

48.

9. The microscope objective according to any one of claims 1 to 6, characterized in that: The focal length fT2 of the second partial lens assembly and the focal length fobj of the microscope objective lens satisfy the following: 3.52≤|fT2 / fobj|≤3.

58.

10. The microscope objective according to any one of claims 1 to 6, characterized in that: The focal length fT3 of the third partial lens assembly and the focal length fobj of the microscope objective lens satisfy the following: 1.68≤|fT3 / fobj|≤1.69.

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