Microscope and microscope objective

Abstract

The utility model relates to the field of microscopes, in particular to a microscope and a microscope objective. The microscope objective comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially and coaxially arranged from the image space to the object space. The first lens is a negative lens, a second lens, a third lens and a fourth lens; the focal length of the microscope objective is f, and the focal lengths of the first lens, the second lens, the third lens and the fourth lens are f1, f2, f3 and f4 in sequence; wherein the result is-3.0 lt; f1 / flt; -2.5,-2.5; 2.0 lt; f2 / flt; 2.8); 101t; 101t; f3 / flt; 50; 1.2 1t; f4 / flt; and 1.5. The microscope objective can meet the requirements of low conjugate distance, low processing cost and long working distance while obtaining high-resolution imaging performance, and is suitable for being matched with a thick cover glass to complete automatic biological cell detection.

Description

Technical Field

[0001] The present application relates to the field of microscopes, and in particular to a microscope and a microscope objective. Background Art

[0002] A microscope is an optical instrument that is mainly used to reflect the image of an object to the human eye or video equipment. The microscope has developed into a compound precision instrument, usually including a combination of multiple lenses.

[0003] The objective lens is the most important part of the microscope, which is used to produce the baseline magnification. The eyepiece is the optical element closest to the human eye or sensor. Its function is to further magnify the real image formed by the objective lens to form a virtual image. The common microscope objective lenses on the market are divided into finite distance and infinite distance objective lenses. Finite distance objective lenses usually have an object-image conjugate distance of 165mm, and infinite distance objective lenses usually need to be equipped with 180mm or 200mm tube lenses to achieve clear imaging. They all have the characteristics of long length and large diameter, and are not suitable for scenes with high space requirements. In the field of automated biological cell detection, it is usually necessary to customize thicker cover glasses. If thicker cover glasses are used, the image quality will decrease, so that the objective lenses on the market usually cannot meet the requirements of clear imaging.

[0004] There are also a few miniature microscope objective lenses used in endoscopes on the market. They have smaller size and higher resolution, but use more lenses and even expensive aspherical lenses. They are difficult to manufacture and have high manufacturing costs. The working distance is also very short, usually less than 1 mm.

[0005] Therefore, how to design a low-cost microscope objective lens that meets the requirements of automated biological cell detection has become a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0006] The present application provides a microscope and a microscope objective lens, which can obtain high-resolution imaging performance, meet the requirements of low conjugate distance, low processing cost and long working distance, and is suitable for completing automated biological cell detection in conjunction with a thick cover glass.

[0007] In a first aspect, the present application provides a microscope objective lens, comprising a first lens, a second lens, a third lens, and a fourth lens coaxially arranged in sequence from the image side to the object side;

[0008] The first lens is a negative lens with negative optical power, and the second lens, the third lens and the fourth lens are positive lenses with positive optical power;

[0009] The focal length of the microscope objective lens is f, and the focal lengths of the first lens, the second lens, the third lens and the fourth lens are f1, f2, f3 and f4 respectively;

[0010] Among them, -3.0 <f1 / f<-2.5;2.0<f2 / f<2.8;10<f3 / f<50;1.2<f4 / f<1.5。

[0011] In some embodiments, corresponding side mirror surfaces of the first lens, the second lens, the third lens, and the fourth lens are spherical surfaces or plane surfaces.

[0012] In some embodiments, the first lens includes an S11 surface and an S12 surface arranged sequentially from the image side to the object side, and both the S11 surface and the S12 surface are convex toward the object side;

[0013] The second lens comprises an S21 surface and an S22 surface arranged in sequence from the image side to the object side, and both the S21 surface and the S22 surface are convex toward the object side;

[0014] The third lens is a doublet lens, and the third lens includes an S31 surface, an S32 surface, and an S33 surface arranged in sequence from the image side to the object side, the S31 surface is convex toward the image side, and the S32 surface and the S33 surface are convex toward the object side;

[0015] The fourth lens comprises an S41 surface and an S42 surface sequentially arranged from the image side to the object side, the S41 surface is convex toward the image side, and the S42 surface is a plane.

[0016] In some embodiments, the doublet lens includes a first sub-lens and a second sub-lens, the bonding surfaces of the first sub-lens and the second sub-lens form the S32 surface, and the difference in refractive index between the first sub-lens and the second sub-lens is greater than a preset value.

[0017] In some embodiments, the centering coefficient K of the first lens satisfies the following conditions:

[0018] K=(D11 / R11-D12 / R12) / 4>0.15;

[0019] Wherein, D11 and R11 are respectively the effective aperture and curvature radius of the S11 surface, and D12 and R12 are respectively the effective aperture and curvature radius of the S12 surface.

[0020] In some embodiments, the center thickness and focal length of each of the first lens, the second lens, the third lens, and the fourth lens satisfy the following conditions:

[0021] -0.15 <D1 / f1<-0.02;0.2<D2 / f2<0.32;0.018<D3 / f3<0.06;0.28<D4 / f4<0.32;

[0022] Wherein, D1, D2, D3 and D4 are the center thicknesses of the first lens, the second lens, the third lens and the fourth lens respectively.

[0023] In some embodiments, the magnification of the microscope objective lens is 12-20 times, and the numerical aperture NA is ≥ 0.35.

[0024] In some embodiments, the total length TTL and the image height H of the microscope objective lens satisfy the following condition: 20<TTL / H<25.

[0025] In some embodiments, an aperture stop is further included between the second lens and the third lens.

[0026] In a second aspect, the present application provides a microscope, comprising the microscope objective lens provided in the above embodiment.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art: the microscope objective lens includes a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with positive optical power, and a cover glass, which are coaxially arranged from the image side to the object side; for automated biological cell detection, a thick cover glass will introduce a large spherical aberration. In the above technical solution, the light from the object side is gradually deflected by the fourth lens and the third lens, which corrects most of the spherical aberration, field curvature and chromatic aberration; the second lens and the first lens are combined with positive and negative lenses to correct the remaining spherical aberration, coma and axial chromatic aberration coma. The number of four lens elements is small, the assembly process is small, and the assembly error is smaller. Through the coordination of the shape of each lens and the optical power, the conjugate total length of the entire micro high-resolution microscope objective lens is less than 105mm, and the NA is greater than 0.35. It can achieve high-resolution imaging performance while meeting the requirements of low conjugate distance, low processing cost and long working distance, and is suitable for observing specimens with thick slides. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0031] Figure 1 A schematic diagram of a microscope objective lens with a magnification of 20X provided in the first embodiment of the present application;

[0032] Figure 2 A schematic diagram of a microscope objective lens with a magnification of 18.5X provided for the second embodiment of the present application;

[0033] Figure 3 A schematic diagram of a microscope objective lens with a magnification of 17X provided for the third embodiment of the present application.

[0034] Description of reference numerals:

[0035] 10 - first lens; 20 - second lens; 30 - aperture; 40 - third lens; 401 - first sub-lens; 402 - second sub-lens; 50 - fourth lens; 60 - cover glass. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0038] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0039] In order to solve the technical problems in the prior art that the microscope objective lens cannot clearly image the sample of the thick cover glass 60, is not suitable for automated biological cell detection, and has high processing cost for special objective lenses. The present application provides a microscope and a microscope objective lens, which can obtain high-resolution imaging performance, meet the requirements of low conjugate distance, low processing cost and long working distance, and are suitable for completing automated biological cell detection with a thick cover glass 60. Among them, the object side refers to the end close to the observed object or the cover glass 60, and the image side refers to the end where the virtual image formed by the microscope objective lens is located, and the image side and the object side are separated at the two ends of the microscope objective lens.

[0040] like Figure 1 As shown, the embodiment of the present application provides a microscope objective lens, which includes a first lens 10, a second lens 20, a third lens 40 and a fourth lens 50, a total of four lens groups, the first lens 10, the second lens 20, the third lens 40 and the fourth lens 50 are arranged in one set interval from the image side to the object side and the four lenses are coaxially arranged. After the light reflected by the observed object passes through the cover glass 60, it passes through the fourth lens 50, the third lens 40, the second lens 20 and the first lens 10 in sequence. Among them, the first lens 10 is a negative lens with negative optical power, and the second lens 20, the third lens 40 and the fourth lens 50 are all positive lenses with positive optical power.

[0041] The focal length of the microscope objective lens composed of the first lens 10, the second lens 20, the third lens 40 and the fourth lens 50 is f, and the focal lengths of the first lens 10, the second lens 20, the third lens 40 and the fourth lens 50 are f1, f2, f3 and f4 respectively. The focal length f of the microscope objective lens and the focal lengths of each lens satisfy the following relationship: -3.0 <f1 / f<-2.5;2.0<f2 / f<2.8;10<f3 / f<50;1.2<f4 / f<1.5。

[0042] In the above technical solution, the light from the object side is gradually deflected by the fourth lens 50 and the third lens 40, which corrects most of the spherical aberration, field curvature and chromatic aberration; the second lens 20 and the first lens 10 are combined with positive and negative lenses to correct the remaining spherical aberration, coma and axial chromatic aberration coma. The number of four lens elements is small, the assembly process is small, and the assembly error is smaller. Through the coordination of the shape of each lens and the optical focal length, the conjugate total length of the entire micro high-resolution microscope objective is less than 105mm, and the NA is greater than 0.35. While achieving high-resolution imaging performance, it can meet the requirements of low conjugate distance, low processing cost and long working distance, and is suitable for observing specimens with high-thick slides. The first lens 10, the second lens 20, the third lens 40 and the fourth lens 50 all use conventional spherical mirrors, and their corresponding side mirror surfaces use standard spherical surfaces or planes, which facilitates the separate processing of each lens and reduces processing costs.

[0043] For a microscope objective lens with a magnification of 20X, the first lens 10 has an S11 surface and an S12 surface, wherein the S11 surface is close to the image side, and the S12 surface is close to the object side, and both of them are convex toward the object side. The second lens 20 includes an S21 surface and an S22 surface, wherein the S21 surface is close to the image side, and the S22 surface is close to the object side, and both of them are convex toward the object side. The third lens 40 adopts a double-cemented lens, and the so-called double-cemented lens refers to the use of two sub-lenses to be bonded and glued by mirror surfaces; specifically, the third lens 40 includes a first sub-lens 401 and a second sub-lens 402, wherein the first sub-lens 401 is close to the image side, and the second sub-lens 402 is close to the object side, and the bonding surface of the first sub-lens 401 and the second sub-lens 402 forms an S32 surface, wherein the first sub-lens 401 is close to the image side as the S31 surface, and the second sub-lens 402 is close to the object side as the S33 surface. The S31 surface is convexly arranged toward the image side, and the S32 surface and the S33 surface are both convexly arranged toward the object side. The refractive index difference between the first sub-lens 401 and the second sub-lens 402 is greater than the set value, which meets the focal length requirements of the double-cemented lens composed of the two and the correction requirements of spherical aberration, field curvature and chromatic aberration. The fourth lens 50 has an S41 surface and an S42 surface, the S41 surface is close to the image side, and the S42 surface is close to the object side. The S41 surface is convex toward the image side, and the S42 surface is set to a plane. The S42 surface of the fourth lens 50 is a plane, which is convenient for the processing of the lens barrel structure and the assembly and positioning of the lens.

[0044] In some embodiments, the material of the first lens 10 is H-K9L glass, which is the cheapest and most common optical glass. The S11 surface of the first lens 10 is concave, and the S12 surface is convex, that is, the first lens 10 adopts a meniscus lens. To facilitate mass mechanical centering processing, the curvatures of the two surfaces of the meniscus lens satisfy the following centering coefficient K condition:

[0045] K = (D11 / R11 - D12 / R12) / 4 > 0.15

[0046] where D11 and R11 are the effective aperture and radius of curvature of the S11 surface of the first lens 10 respectively, and D12 and R12 are the effective aperture and radius of curvature of the S12 surface of the first lens 10 respectively.

[0047] The central thickness and focal length of each of the first lens 10, the second lens 20, the third lens 40, and the fourth lens 50 satisfy the following conditions:

[0048] -0.15 < D1 / f1 < -0.02; 0.2 < D2 / f2 < 0.32; 0.018 < D3 / f3 < 0.06; 0.28 < D4 / f4 < 0.32;

[0049] where D1, D2, D3, and D4 are the central thicknesses of the first lens 10, the second lens 20, the third lens 40, and the fourth lens 50 respectively, and f1, f2, f3, and f4 are the focal lengths of the first lens 10, the second lens 20, the third lens 40, and the fourth lens 50 respectively.

[0050] The total length TTL of the microscope objective and the image height H satisfy the following condition: 20 < TTL / H < 25.

[0051] Furthermore, the optical magnification N of the objective satisfies the following condition: 12X < N < 20X. Under this condition, a relatively large magnification and a relatively wide field of view can be achieved, and the cell detection time can be reduced. The above microscope objective is applicable to a cover glass 60 with a thickness of 1.0 mm - 1.5 mm and can meet the requirements of high-resolution imaging.

[0052] The following will elaborate on the detailed specifications of each lens in combination with specific embodiments.

[0053] Embodiment 1: The magnification is 20X, as Figure 1 shown in Table 1 below:

[0054] Table 1

[0055]

[0056]

[0057] Among the above-selected lenses, the working distance is 3mm, and the center thickness from the image plane to the S11 surface of the first lens 10 is 88mm. The S11 surface of the first lens 10 is a concave surface with a clear aperture of 6mm and a curvature radius of -3.221mm. The S12 surface is a convex surface with a curvature radius of -6.632mm and a clear aperture of 7.5mm. The center thickness of the first lens 10 is 0.498mm and the material is H-K9L. The center thickness from the S12 surface of the first lens 10 to the S21 surface of the second lens 20 is 1.437mm, that is, the air gap between the first lens 10 and the second lens 20.

[0058] The S21 surface of the second lens 20 is concave, with a curvature radius of -14.097 mm and a clear aperture of 7.5 mm. The S22 surface has a curvature radius of -5.638 mm and a clear aperture of 7.5 mm. The center thickness of the second lens 20 is 2.511 mm and the material is H-LAK52. The center thickness from the S22 surface of the second lens 20 to the aperture 30 is 0.054 mm, and the center thickness to the S31 surface of the third lens 40 is 2.742 mm.

[0059] The curvature radius of the S31 surface of the third lens 40 is 14.061mm, and the light aperture is 7.5mm. The curvature radius of the S32 surface is -4.347mm, and the light aperture is 7.5mm. The curvature radius of the S7 surface is -15.765mm, and the light aperture is 7.5mm. The center thickness from the S31 surface to the S32 surface of the third lens 40 is 2.958mm, the center thickness from the S32 surface to the S33 surface is 0.512mm, and the center thickness from the S33 surface of the third lens 40 to the S41 surface of the fourth lens 50 is 0.1mm. The material of the positive lens in the third lens 40, that is, the first sub-lens 401, is H-K9L, and the material of the negative lens, that is, the second sub-lens 402, is H-ZF52.

[0060] The S41 surface of the fourth lens 50 has a curvature radius of 4.909 mm and a light-clearing aperture of 7.5 mm. The S42 surface is a plane and has a light-clearing aperture of 7.5 mm. The center thickness of the fourth lens 50 is 2.041 mm and the material is H-LAK52.

[0061] The cover glass 60 used in conjunction has a thickness of 1.4 mm and is made of PMMA.

[0062] Calculation shows that the first lens 10 satisfies the parameter relationship: D1 / f1=-0.039, f1 / f=-2.834; the second lens 202 satisfies the parameter relationship: D2 / f2=0.219, f2 / f=2.54; the third lens 40 satisfies the parameter relationship: D3 / f3=0.058, f3 / f=13.33; the fourth lens 50 satisfies the parameter relationship: D4 / f4=0.303, f4 / f=1.496.

[0063] The final microscope objective has a total length of 105mm, a system optical magnification of 20X, a working distance of 3mm, a cover glass 60 with a thickness of 1.4mm, a numerical aperture NA of 0.39, an MTF greater than 0.25 at a full field of view of 750lp / mm, a field curvature less than about 2um, which is less than the depth of field, satisfying a flat image field.

[0064] Example 2: The magnification is 18.5X, as Figure 2 As shown in Table 2 below:

[0065] Table 2

[0066]

[0067] Among the above-selected lenses, the working distance is 3mm, and the center thickness from the image plane to the S11 surface of the first lens 10 is 82mm. The S11 surface of the first lens 10 is concave, the light aperture is 6mm, the radius of curvature is -3.194mm, the S12 surface is convex, the radius of curvature is -6.142mm, the light aperture is 7.5mm, the center thickness of the first lens 10 is 0.453mm, the material is H-K9L, and the center thickness from the S12 surface of the first lens 10 to the S21 surface of the second lens 20 is 1.248mm, that is, the air gap between the first lens 10 and the second lens 20.

[0068] The S21 surface of the second lens 20 is concave, with a curvature radius of -13.458 mm and a clear aperture of 7.5 mm. The S22 surface has a curvature radius of -5.481 mm and a clear aperture of 7.5 mm. The center thickness of the second lens 20 is 2.282 mm and the material is H-LAK52. The center thickness from the S22 surface of the second lens 20 to the aperture 30 is 0 mm, and the center thickness to the S31 surface of the third lens 40 is 2.616 mm.

[0069] The curvature radius of the S31 surface of the third lens 40 is 13.931mm, and the aperture is 7.5mm; the curvature radius of the S32 surface is -4.388mm, and the aperture is 7.5mm; the curvature radius of the S33 surface is -16.492mm, and the aperture is 7.6mm; the center thickness from the S31 surface to the S32 surface of the third lens 40 is 2.924mm, the center thickness from the S32 surface to the S33 surface is 0.512mm, and the center thickness from the S33 surface of the third lens 40 to the S41 surface of the fourth lens 50 is 0.1mm. The material of the positive lens in the third lens 40, that is, the first sub-lens 401, is H-K9L, and the material of the negative lens, that is, the second sub-lens 402, is H-ZF52.

[0070] The S41 surface of the fourth lens 50 has a curvature radius of 4.942 mm and a clear aperture of 7.5 mm. The S42 surface is a plane and has a clear aperture of 7.5 mm. The center thickness of the fourth lens 50 is 2.023 mm and the material is H-LAK52.

[0071] The cover glass 60 used in conjunction has a thickness of 1.4 mm and is made of PMMA.

[0072] Calculation shows that the first lens 10 satisfies the parameter relationship: D1 / f1=-0.033, f1 / f=-2.904; the second lens 202 satisfies the parameter relationship: D2 / f2=0.202, f2 / f=2.45; the third lens 40 satisfies the parameter relationship: D3 / f3=0.053, f3 / f=13.8; the fourth lens 50 satisfies the parameter relationship: D4 / f4=0.303, f4 / f=1.448.

[0073] The final miniature high-resolution microscope objective has a total length of 102.7 mm, a system optical magnification of 18.5X, a working distance of 3 mm, a cover glass 60 with a thickness of 1.4 mm, an MTF greater than 0.23 at a full field of view of 750 lp / mm, a field curvature of 2 um, which is less than the depth of field and satisfies the flat field requirement. This embodiment has a shorter total length and a larger field of view than the previous embodiment.

[0074] Example 3: The magnification is 17X, as Figure 3 As shown in Table 3 below:

[0075] Table 3

[0076]

[0077] Among the above-selected lenses, the working distance is 3mm, and the center thickness from the image plane to the S11 surface of the first lens 10 is 84mm. The S11 surface of the first lens 10 is concave, the light aperture is 6mm, the radius of curvature is -4.000mm, the S12 surface is convex, the radius of curvature is -9.793mm, the light aperture is 7.5mm, the center thickness of the first lens 10 is 1.597mm, the material is H-K9L, and the center thickness from the S12 surface of the first lens 10 to the S21 surface of the second lens 20 is 1.205mm, that is, the air gap between the first lens 10 and the second lens 20.

[0078] The S21 surface of the second lens 20 is a plane with a clear aperture of 7.5 mm. The S22 surface has a curvature radius of -8.085 mm and a clear aperture of 7.5 mm. The center thickness of the second lens 20 is 3.458 mm and the material is H-LAK52. The center thickness from the S22 surface of the second lens 20 to the aperture 30 is 0.225 mm, and the center thickness to the S31 surface of the third lens 40 is 3.121 mm.

[0079] The curvature radius of the S31 surface of the third lens 40 is 13.184mm, and the aperture is 7.5mm; the curvature radius of the S32 surface is -5.03mm, and the aperture is 7.5mm; the curvature radius of the S33 surface is -30.649mm, and the aperture is 7.5mm; the center thickness from the S31 surface to the S32 surface of the third lens 40 is 2.823mm, the center thickness from the S32 surface to the S33 surface is 1.500mm, and the center thickness from the S33 surface of the third lens 40 to the S41 surface of the fourth lens 50 is 0.1mm. The material of the positive lens in the third lens 40, that is, the first sub-lens 401, is H-K9L, and the material of the negative lens, that is, the second sub-lens 402, is H-LAK52.

[0080] The S41 surface of the fourth lens 50 has a curvature radius of 5.203 mm and a light-clearing aperture of 6 mm, the S42 surface is a plane and has a light-clearing aperture of 7.5 mm, the center thickness of the fourth lens 50 is 2.196 mm, and the material is H-LAK52.

[0081] The cover glass 60 used in conjunction has a thickness of 1.4 mm and is made of PMMA.

[0082] Calculation shows that the first lens 10 satisfies the parameter relationship: D1 / f1=-0.111, f1 / f=-2.84; the second lens 202 satisfies the parameter relationship: D2 / f2=0.312, f2 / f=2.18; the third lens 40 satisfies the parameter relationship: D3 / f3=0.058, f3 / f=43.8; the fourth lens 50 satisfies the parameter relationship: D4 / f4=0.308, f4 / f=1.407.

[0083] The final miniature high-resolution microscope objective lens has a total length of 105 mm, a system optical magnification of 17X, a working distance of 3 mm, a cover glass 60 thickness of 1.4 mm, a numerical aperture of 0.39, an MTF greater than 0.22 at 750 lp / mm in the full field of view, a field curvature less than about 2 um, less than the depth of field, and meets the flat field requirement. This embodiment has a larger field of view and a higher resolution than the above two embodiments, and the second lens 20 is a platform lens, which is simpler to process and assemble.

[0084] The present application also provides a microscope, including the microscope objective lens provided in the above-mentioned embodiment. Other parts of the microscope, such as the eyepiece, etc., can refer to the existing microscope settings, and the present application will not elaborate on them one by one.

[0085] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0086] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A microscope objective lens, characterized in that: It includes a first lens, a second lens, a third lens and a fourth lens which are coaxially arranged in sequence from the image side to the object side; The first lens is a negative lens with negative optical power, and the second lens, the third lens and the fourth lens are positive lenses with positive optical power; The focal length of the microscope objective lens is f, and the focal lengths of the first lens, the second lens, the third lens and the fourth lens are f1, f2, f3 and f4 respectively; Among them, -3.0 <f1 / f<-2.5;2.0<f2 / f<2.8;10<f3 / f<50;1.2<f4 / f<1.5。 2. The microscope objective lens according to claim 1, characterized in that The corresponding side mirror surfaces of the first lens, the second lens, the third lens and the fourth lens are spherical surfaces or plane surfaces.

3. The microscope objective lens according to claim 1, characterized in that: The first lens comprises an S11 surface and an S12 surface arranged in sequence from the image side to the object side, and both the S11 surface and the S12 surface are convex toward the object side; The second lens comprises an S21 surface and an S22 surface arranged in sequence from the image side to the object side, and both the S21 surface and the S22 surface are convex toward the object side; The third lens is a doublet lens, and the third lens includes an S31 surface, an S32 surface, and an S33 surface arranged in sequence from the image side to the object side, the S31 surface is convex toward the image side, and the S32 surface and the S33 surface are convex toward the object side; The fourth lens comprises an S41 surface and an S42 surface sequentially arranged from the image side to the object side, the S41 surface is convex toward the image side, and the S42 surface is a plane.

4. The microscope objective lens according to claim 3, characterized in that: The doublet lens includes a first sub-lens and a second sub-lens, the bonding surfaces of the first sub-lens and the second sub-lens form the S32 surface, and the difference in refractive index between the first sub-lens and the second sub-lens is greater than a preset value.

5. The microscope objective lens according to claim 3, characterized in that: The centering coefficient K of the first lens satisfies the following conditions: K=(D11 / R11-D12 / R12) / 4>0.15; Wherein, D11 and R11 are respectively the effective aperture and curvature radius of the S11 surface, and D12 and R12 are respectively the effective aperture and curvature radius of the S12 surface.

6. The microscope objective lens according to claim 1, characterized in that: The center thickness and focal length of each of the first lens, the second lens, the third lens and the fourth lens satisfy the following conditions: -0.15 <D1 / f1<-0.02;0.2<D2 / f2<0.32;0.018<D3 / f3<0.06; 0.28 <D4 / f4<0.32; Wherein, D1, D2, D3 and D4 are the center thicknesses of the first lens, the second lens, the third lens and the fourth lens respectively.

7. The microscope objective lens according to claim 1, characterized in that: The magnification of the microscope objective lens is 12-20 times, and the numerical aperture NA is ≥ 0.

35.

8. The microscope objective lens according to claim 1, characterized in that: The total length TTL and image height H of the microscope objective lens satisfy the following condition: 20<TTL / H<25.

9. The microscope objective lens according to any one of claims 1 to 8, characterized in that: The invention also includes an aperture stop disposed between the second lens and the third lens.

10. A microscope, characterized in that: The microscope objective lens comprises the microscope objective lens as described in any one of claims 1 to 9.

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