microscope objectives

Abstract

This invention relates to a microscope objective, comprising a first lens group (T1) with positive optical power, a second lens group (T2) with positive optical power, and a third lens group (T3) with negative optical power, arranged sequentially along the optical axis from the object side to the image side. The third lens group (T3) includes a double Gaussian structure composed of two optical elements. The microscope objective of this invention has the advantages of a large field of view and a large numerical aperture.

Description

Technical Field

[0001] This invention relates to the field of microscopy, and more particularly to a microscope objective. Background Technology

[0002] Due to the increasing demands for observation resolution and imaging speed in the life sciences and industrial fields, the trend in microscope objectives is towards larger fields of view and larger apertures (NA). However, while achieving large numerical aperture apochromatic effects, it is also necessary to ensure good fluorescence performance of the microscope objectives and good manufacturability of the structure. This is crucial for the production of large numerical aperture microscope objectives. Summary of the Invention

[0003] The purpose of this invention is to provide a microscope objective.

[0004] To achieve the above-mentioned objective, the present invention provides a microscope objective, comprising a first lens group with positive optical power, a second lens group with positive optical power, and a third lens group with negative optical power arranged sequentially along the optical axis from the object side to the image side. The third lens group includes a double Gaussian structure composed of two optical elements.

[0005] According to one aspect of the invention, along the optical axis from the object side to the image side, the first lens group includes a first optical element, a second optical element, and a third optical element, and the second lens group includes a fourth optical element, a fifth optical element, and a sixth optical element.

[0006] According to one aspect of the invention, the first optical element is a cemented lens assembly having positive optical power;

[0007] The object side of the first optical element is a plane, and the image side is a hemispherical surface.

[0008] According to one aspect of the invention, the first optical element comprises a plano-convex lens located on the object side and a super-hemispherical lens located on the image side.

[0009] According to one aspect of the invention, the second optical element and the third optical element are each a lens, both having positive optical power.

[0010] According to one aspect of the invention, the fourth optical element is a cemented lens assembly;

[0011] Both the fifth and sixth optical elements are cemented doublets and have symmetrical optical power.

[0012] The fourth, fifth, and sixth optical elements have biconvex shapes.

[0013] According to one aspect of the present invention, the fourth optical element comprises two positive power lenses and one negative power lens, wherein the two positive power lenses are both made of materials with an Abbe number greater than 70;

[0014] The fifth optical element consists of a negative power lens located on the object side and a positive power lens located on the image side;

[0015] The sixth optical element consists of a positive power lens located on the object side and a negative power lens located on the image side.

[0016] According to one aspect of the invention, the third lens group includes a seventh cemented lens group and an eighth cemented lens group arranged sequentially from the object side along the optical axis with symmetrical positive and negative optical power.

[0017] The concave surfaces of the seventh cemented lens group and the eighth cemented lens group face each other, forming a double Gaussian structure;

[0018] The seventh and eighth cemented lens groups are each double cemented lens groups.

[0019] According to one aspect of the invention, the seventh cemented lens group consists of a positive power lens located on the object side and a negative power lens located on the image side.

[0020] The eighth cemented lens group consists of a negative power lens on the object side and a positive power lens on the image side.

[0021] According to one aspect of the invention, the third lens group further includes a ninth optical element of positive power located on the image side of the eighth cemented lens group, the ninth optical element being a lens or a cemented doublet.

[0022] According to one aspect of the invention, the third lens group further includes a tenth optical element with positive or negative optical power located on the object side of the seventh cemented lens group;

[0023] The tenth optical element is a lens with a crescent shape and a concave side.

[0024] According to one aspect of the invention, the distance D from the object surface to the last surface of the microscope objective and the focal length fobj of the microscope objective satisfy the following relationship: 10 <D / fobj<36.2;

[0025] The focal length fobj of the microscope objective lens satisfies the following condition: fobj > 1.7;

[0026] The objective lens's numerical aperture NA satisfies the following condition: 1 <NA<1.5。

[0027] According to one aspect of the invention, the projection height H2 of the peripheral ray of the central field of view on the last lens surface of the second lens group satisfies the following relationships with the lowest projection height H1 of the peripheral ray of the central field of view on the lens surface of the third lens group and the projection height H3 of the peripheral ray of the central field of view on the last lens surface of the first lens group: 0.1 < |H2 / H3| < 1.5; 0.1 < |H1 / H2| < 0.8.

[0028] According to one aspect of the invention, the focal length fL1 of the first lens of the first lens group and the radius value RL1 of the surface facing the object side satisfy the following relationship with the focal length fobj of the microscope objective: 1 < |fL1 / fobj|; |RL1 / fobj| = ∞.

[0029] According to one aspect of the invention, the combined focal length fT1 of the first lens group and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT1 / fobj| < 30.

[0030] According to one aspect of the invention, the combined focal length fT2 of the second lens group and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT2 / fobj|;

[0031] According to one aspect of the invention, the combined focal length fT3 of the third lens group and the focal length fobj of the microscope objective satisfy the following relationship: 0.1 < |fT3 / fobj|.

[0032] According to one aspect of the present invention, it is applied to biological fluorescence observation, with a maximum field of view of 30 and an application wavelength of 436-656 nm.

[0033] According to the present invention, the first lens group consists of a cemented doublet and at least one single lens, mainly used to increase the object-side numerical aperture. The second lens group consists of at least one cemented doublet and a single lens, mainly used to eliminate chromatic aberration. The third lens group consists of a double Gaussian structure and a single lens or cemented doublet, which can achieve a maximum field of view of 30, a maximum numerical aperture of 1.5, and good fluorescence performance in the 405nm-1000nm wavelength range. Attached Figure Description

[0034] Figure 1 A schematic diagram illustrating the structure of a microscope objective lens according to a first embodiment of the present invention;

[0035] Figure 2 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to a first embodiment of the present invention.

[0036] Figure 3A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a first embodiment of the present invention in a field of view.

[0037] Figure 4 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a first embodiment of the present invention;

[0038] Figure 5 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to a first embodiment of the present invention;

[0039] Figure 6 A schematic diagram illustrating the structure of a microscope objective lens according to a second embodiment of the present invention;

[0040] Figure 7 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to a second embodiment of the present invention.

[0041] Figure 8 A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a second embodiment of the present invention in the field of view.

[0042] Figure 9 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a second embodiment of the present invention;

[0043] Figure 10 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to a second embodiment of the present invention;

[0044] Figure 11 A schematic diagram illustrating the structure of a microscope objective lens according to a third embodiment of the present invention;

[0045] Figure 12 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to a third embodiment of the present invention.

[0046] Figure 13 A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a third embodiment of the present invention in the field of view.

[0047] Figure 14 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a third embodiment of the present invention;

[0048] Figure 15 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to a third embodiment of the present invention;

[0049] Figure 16 A schematic diagram illustrating the structure of a microscope objective lens according to a fourth embodiment of the present invention;

[0050] Figure 17 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to a fourth embodiment of the present invention.

[0051] Figure 18 A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a fourth embodiment of the present invention in the field of view.

[0052] Figure 19 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a fourth embodiment of the present invention;

[0053] Figure 20 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to a fourth embodiment of the present invention;

[0054] Figure 21 A schematic diagram illustrating the structure of a microscope objective lens according to a fifth embodiment of the present invention;

[0055] Figure 22 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to a fifth embodiment of the present invention.

[0056] Figure 23 A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a fifth embodiment of the present invention in the field of view.

[0057] Figure 24 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a fifth embodiment of the present invention;

[0058] Figure 25 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to a fifth embodiment of the present invention;

[0059] Figure 26 A schematic diagram illustrating the structure of a microscope objective lens according to a sixth embodiment of the present invention;

[0060] Figure 27 A schematic diagram illustrating the lateral aberration at zero field of view of a microscope objective lens according to the sixth embodiment of the present invention.

[0061] Figure 28 A schematic diagram illustrating the lateral aberration of a microscope objective lens according to a sixth embodiment of the present invention in the field of view.

[0062] Figure 29 A schematic diagram illustrating the field curvature distortion of a microscope objective lens according to a sixth embodiment of the present invention;

[0063] Figure 30 The diagram schematically illustrates the chromatic aberration curve of a microscope objective lens according to the sixth embodiment of the present invention. Detailed Implementation

[0064] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0065] When describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" express orientations or positional relationships based on the orientations or positional relationships shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on the present invention.

[0066] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the embodiments of the present invention are not limited to the following embodiments.

[0067] See Figure 1 The microscope objective of this invention is an infinity conjugate objective. During observation, the medium between the observed object and the objective can be either air or a liquid. When the medium is air, the numerical aperture is less than 1; when the medium is a liquid, the numerical aperture can reach its maximum value. The microscope objective includes a first lens group T1 with positive optical power arranged sequentially from the object side to the image side along the optical axis, which includes at least one lens with positive optical power; a second lens group T2 with positive optical power, which includes at least one lens or a cemented lens group, wherein the cemented lens group refers to a cemented doublet or a multi-lens cemented lens group, and its shape can be meniscus or biconvex; and a third lens group T3 with negative optical power.

[0068] Along the optical axis from the object side to the image side, the first lens group T1 includes a first optical element G1, a second optical element G2, and a third optical element G3, and the second lens group T2 includes a fourth optical element G4, a fifth optical element G5, and a sixth optical element G6. In this invention, the third lens group T3 includes a double Gaussian structure composed of two optical elements.

[0069] In this invention, the first optical element G1 is a cemented lens assembly with positive optical power. The object-side surface of the first optical element G1 is planar, and the image-side surface is hemispherical (or nearly hemispherical). Specifically, the first optical element G1 consists of a plano-convex lens on the object side and a super-hemispherical lens on the image side. The second optical element G2 and the third optical element G3 are each a single lens or a cemented lens assembly, both with positive optical power. That is, in the first lens group T1, at least one single lens or cemented lens assembly follows the first optical element G1.

[0070] In this invention, the fourth optical element G4 is a cemented triplet lens group, and the fifth and sixth optical elements G5 and G6 are cemented doublet lens groups, with symmetrical optical powers. The shapes of the fourth, fifth, and sixth optical elements G4 and G5 include biconvex shapes. The fourth optical element G4 consists of two positive power lenses and one negative power lens; both positive power lenses are made of materials with an Abbe number greater than 70. The fifth optical element G5 consists of a negative power lens located on the object side and a positive power lens located on the image side. The sixth optical element G6 consists of a positive power lens located on the object side and a negative power lens located on the image side.

[0071] In this invention, the third lens group T3 comprises at least two lens groups. Specifically, the third lens group T3 includes a seventh cemented lens group G7 and an eighth cemented lens group G8 arranged sequentially along the optical axis from the object side, exhibiting symmetrical positive and negative optical power. That is, the optical power of these two lens groups is one positive and one negative, and their concave surfaces face each other, forming a double Gaussian structure. The seventh cemented lens group G7 and the eighth cemented lens group G8 are each either a cemented lens group or a multi-cemented lens group. The seventh cemented lens group G7 may consist of a positive optical power lens located on the object side and a negative optical power lens located on the image side. The eighth cemented lens group G8 may consist of a negative optical power lens located on the object side and a positive optical power lens located on the image side.

[0072] In this invention, the third lens group T3 further includes at least one optical element located on the image side of the eighth cemented lens group G8. In some embodiments, this optical element is a ninth optical element G9 with positive optical power, and the ninth optical element G9 is a lens or a cemented doublet.

[0073] In this invention, the third lens group T3 also includes at least one optical element located on the object side of the seventh cemented lens group G7. In some embodiments, the optical element is a tenth optical element G10 with positive or negative optical power. The tenth optical element G10 is a lens with a meniscus shape and a concave image side. In some embodiments, its optical power can be negative.

[0074] In the present invention, the distance D from the object surface to the last surface of the microscope objective and the focal length fobj of the microscope objective satisfy the following relationship: 10 < D / fobj < 36.2. The focal length fobj of the microscope objective satisfies the following condition: fobj > 1.7. The object-side numerical aperture NA of the microscope objective satisfies the following condition: 1 < NA < 1.5.

[0075] In the present invention, the projection height H2 of the marginal ray of the central field on the last lens surface of the second lens group T2 respectively satisfies the following relationships with the lowest projection height H1 of the marginal ray of the central field on the lens surface in the third lens group T3 and the projection height H3 of the marginal ray of the central field on the last lens surface of the first lens group T1: 0.1 < |H2 / H3| < 1.5; 0.1 < |H1 / H2| < 0.8. The ray height reaches the maximum value between the last set of lenses of the first lens group T1 and the last lens surface of the second lens group T2.

[0076] In the present invention, the focal length fL1 of the first lens of the first lens group T1 and the radius value RL1 of the surface facing the object side respectively satisfy the following relationships with the focal length fobj of the microscope objective: 1 < |fL1 / fobj|; |RL1 / fobj| = ∞.

[0077] In the present invention, the combined focal length fT1 of the first lens group T1 and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT1 / fobj| < 30. The combined focal length fT2 of the second lens group T2 and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT2 / fobj|. The combined focal length fT3 of the third lens group T3 and the focal length fobj of the microscope objective satisfy the following relationship: 0.1 < |fT3 / fobj|.

[0078] In summary, the microscope objective of this invention comprises three lens groups. The first lens group T1 consists of a cemented doublet and at least one single lens, used to increase the numerical aperture on the object side. The second lens group T2 consists of at least one cemented doublet and a single lens, used to eliminate chromatic aberration. The third lens group T3 consists of a double Gaussian structure and a single lens or a cemented doublet. The microscope objective of this invention has a maximum field of view of 30, a maximum numerical aperture of 1.5, and good fluorescence performance in the 405nm-1000nm wavelength range. Furthermore, the working distance of the microscope objective can reach 0.17mm or more, including working distances of 0mm-0.17mm, where the working distance is the distance from the coverslip to the edge of the first lens group of the objective. The lens materials of this invention are required to have low near-ultraviolet transmittance and good fluorescence performance. A lens configuration of 16-18 elements offers the best cost-performance ratio, suitable for biological fluorescence observation. It allows for a maximum field of view of up to 30, a maximum numerical aperture of 1.5, and apochromatic imaging within the 436-656nm wavelength range, with good imaging performance in the near-infrared and near-ultraviolet bands. Of course, additional lenses can be added to further enhance performance.

[0079] The microscope objectives of the present invention are described in detail below with six sets of embodiments, where the surfaces of each lens are represented by S1, S2, ..., SN, and the cemented surface of the cemented lens group is referred to as one surface. In the following embodiments, the first lens group T1 is mainly used to provide optical power and reduce the numerical aperture for the rear portion; the second lens group T2 is mainly used to correct chromatic aberration, and the third lens group T3 is mainly used to correct field curvature. The working distance of the fluorescence biological microscope objective of the present invention is 0.17 mm. The working wavelength (spectral range) of the microscope objective is 400 nm-1000 nm, and in some embodiments, it can be 436 nm-1000 nm. The imaging effect is best in the 436-656 nm wavelength range, the field of view is 26.5, and the numerical aperture is 1.3.

[0080] The parameters for each implementation method that meets the above conditions are shown in Table 1 below:

[0081]

[0082]

[0083] Table 1

[0084] First implementation method

[0085] See Figure 1 In this embodiment, the microscope objective consists of 18 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S28.

[0086] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape. It consists of a plano-convex first lens L1 located on the object side and a hemispherical second lens L2 located on the image side. The second and third optical elements G2 and G3 are both single lenses with positive power, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 located on the object side and a positive power ninth lens L9 located on the image side. The sixth optical element G6 is a cemented doublet, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublet groups. The tenth optical element G10 is a meniscus-shaped twelfth lens L12 with a concave image side. The seventh cemented doublet group G7 is a cemented doublet, consisting of a thirteenth lens L13 with positive optical power on the object side and a fourteenth lens L14 with negative optical power on the image side. The eighth cemented doublet group G8 is a cemented doublet, consisting of a fifteenth lens L15 with negative optical power on the object side and a sixteenth lens L16 with positive optical power on the image side. The eighth cemented doublet group G8 and the seventh cemented doublet group G7 form two symmetrical cemented doublet groups. The ninth optical element G9 is a cemented doublet group with positive optical power.

[0087] In this embodiment, the system focal length is 3mm, the working distance is 0.17mm, the numerical aperture is 1.3, and the lens thickness and radius of the microscope objective are shown in Table 2 below:

[0088] surface Radius (mm) Thickness (mm) Nd Vd S28 50.269 1 1.61 44.3 S27 19.325 2 1.43 95 S26 -70.444 0.15 S25 8.058 3.6 1.74 32.3 S24 15.598 1 1.60 65.4 S23 2.781 1.8 S22 -2.895 1 1.74 32.3 S21 -18.565 4.2 1.43 95 S20 -5.987 0.15 S19 -17.586 2 1.43 95 S18 -9.258 0.15 S17 -20.158 1.2 1.43 95 S16 14.215 5 1.74 32.3 S15 -14.687 0.15 S14 65.251 1.2 1.43 95 S13 -7.895 4.8 1.61 44.3 S12 -25.685 0.15 S11 17.154 4.7 1.43 95 S10 -12.158 1.2 1.61 44.3 S9 15.235 4.6 1.43 95 S8 -18.256 0.15 S7 50.235 2.5 1.43 95 S6 -13.087 0.15 S5 25.258 2.6 1.43 95 S4 -62.841 0.15 S3 4.542 5 1.88 40.8 S2 2.031 0.7 1.52 64.1 S1 Infinity 0.17

[0089] Table 2

[0090] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0091] Figure 2 This is a lateral aberration diagram of the microscope objective lens in the first embodiment, where the horizontal axes 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.

[0092] Figure 3This is a lateral aberration diagram of the first embodiment of the microscope objective lens, with a scale bar of ±5 micrometers. As can be seen from the diagram, the curve is close to the horizontal axis, indicating good imaging performance.

[0093] Figure 4 This is a field curvature distortion diagram of the microscope objective lens according to the first embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units of 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 less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, the vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 10 μm and a minimum value of -10 μm. The right figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 0.5%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 0.5% and a minimum of -0.5%.

[0094] Figure 5 This is a chromatic aberration curve of the microscope objective lens according to the first embodiment. The chromatic aberration correction is good across the entire wavelength, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0095] The objective lens of the biological fluorescence microscope in this embodiment has a large numerical aperture (NA = 1.3), and in some preferred embodiments, the numerical aperture can be greater than 1.5.

[0096] Second implementation method

[0097] See Figure 6 In this embodiment, the microscope objective consists of 17 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S27.

[0098] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape, consisting of a plano-convex first lens L1 on the object side and a hemispherical second lens L2 on the image side. The second and third optical elements G2 and G3 are both positive power lenses, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 on the object side and a positive power ninth lens L9 on the image side. The sixth optical element G6 is a cemented doublet, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublet groups. The tenth optical element G10 is a meniscus-shaped twelfth lens L12 with a concave image side. The seventh cemented doublet group G7 is a negative optical power cemented doublet, consisting of a thirteenth lens L13 with positive optical power on the object side and a fourteenth lens L14 with negative optical power on the image side. The eighth cemented doublet group G8 is a positive optical power cemented doublet, consisting of a fifteenth lens L15 with negative optical power on the object side and a sixteenth lens L16 with positive optical power on the image side. The eighth cemented doublet group G8 and the seventh cemented doublet group G7 form two symmetrical cemented doublet groups. The ninth optical element G9 is a single lens with positive optical power, namely the seventeenth lens L17. In this embodiment, the working distance of the microscope objective is 0.17 mm, the spectral range is 436 nm-656 nm, and the field of view is 25.

[0099] In this embodiment, the system focal length is 3mm, the working distance is 0.17mm, the numerical aperture is 1.3, and the lens thickness and radius of the microscope objective are shown in Table 3 below:

[0100]

[0101]

[0102] Table 3

[0103] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0104] Figure 7This is a lateral aberration diagram of the microscope objective lens in the second embodiment, where the horizontal axes 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.

[0105] Figure 8 This is a lateral aberration diagram of the microscope objective lens in the second embodiment, with a scale bar of ±5 micrometers. As can be seen from the diagram, the curve is close to the horizontal axis, indicating good imaging performance.

[0106] Figure 9 This is a field curvature distortion diagram of the microscope objective lens according to the second embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units of μm. The axial difference between the optimal focal point at the edge of the field of view and the optimal focal point at the center of the field of view is less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, 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 figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 0.2%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 0.2% and a minimum of -0.2%.

[0107] Figure 10 This is a chromatic aberration curve of the microscope objective lens according to the second embodiment. The chromatic aberration correction is good across the entire wavelength, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0108] The objective lens of this embodiment of the biological fluorescence microscope has a large objective field of view (0.21 mm) and a large numerical aperture (NA = 1.3). In some preferred embodiments, the field of view can be greater than 0.5 mm and the numerical aperture can be greater than 1.45.

[0109] Third implementation method

[0110] See Figure 11 In this embodiment, the microscope objective consists of 16 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S25.

[0111] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape, consisting of a plano-convex first lens L1 on the object side and a hemispherical second lens L2 on the image side. The second and third optical elements G2 and G3 are both positive power lenses, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 on the object side and a positive power ninth lens L9 on the image side. The sixth optical element G6 is a cemented doublet, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublet groups. The seventh cemented doublet group G7 is a cemented doublet, consisting of a twelfth lens L12 with positive optical power on the object side and a thirteenth lens L13 with negative optical power on the image side. The eighth cemented doublet group G8 is a cemented doublet, consisting of a fourteenth lens L14 with negative optical power on the object side and a fifteenth lens L15 with positive optical power on the image side. The eighth cemented doublet group G8 and the seventh cemented doublet group G7 form two symmetrical cemented doublet groups. The ninth optical element G9 is a single lens with positive optical power, namely the sixteenth lens L16.

[0112] In this embodiment, the system focal length f = 3 mm, the working distance is 0.17 mm, the numerical aperture is 1.3, and the lens thickness and radius of the microscope objective are shown in Table 4 below:

[0113] surface Radius (mm) Thickness (mm) Nd Vd S25 80.658 1.8 1.43 95 S24 -15.265 0.15 S23 7.298 2.8 1.74 32.3 S22 14.785 1 1.60 65.4 S21 2.971 2.7 S20 -2.593 1 1.74 32.3 S19 33.786 3.8 1.43 95 S18 -6.352 0.15 S17 -30.598 1.2 1.43 95 S16 27.356 4.5 1.74 32.3 S15 -9.658 0.1 S14 78.625 4.5 1.43 95 S13 -9.587 1.2 1.52 64.1 S12 43.652 0.15 S11 15.656 6.2 1.43 95 S10 -15.656 1.2 1.61 44.3 S9 11.587 6 1.43 95 S8 -32.689 0.15 S7 13.025 3.0 1.43 95 S6 -67.560 0.15 S5 17.359 2.2 1.43 95 S4 158.212 0.15 S3 4.056 4.8 1.88 40.8 S2 1.689 0.55 1.52 64.1 S1 Infinity 0.17

[0114] Table 4

[0115] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0116] Figure 12 This is a lateral aberration diagram of the microscope objective lens in the third embodiment, where the horizontal axes 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.

[0117] Figure 13 This is a lateral aberration diagram of the first field of view of the microscope objective lens of the third embodiment, 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.

[0118] Figure 14 This is a field curvature distortion diagram of the microscope objective lens according to the third embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units 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 less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, the vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 10 μm and a minimum value of -10 μm. The right figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 1%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 1% and a minimum of -1%.

[0119] Figure 15 This is a chromatic aberration curve of the microscope objective lens according to the third embodiment. The chromatic aberration correction is good across the entire wavelength, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0120] The objective lens of the biological fluorescence microscope in this embodiment has a large objective field of view (0.42 mm) and a large numerical aperture (NA = 1.3). In some preferred embodiments, the field of view can be greater than 0.5 mm and the numerical aperture can be greater than 1.45.

[0121] Fourth implementation method

[0122] See Figure 16 In this embodiment, the microscope objective consists of 17 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S27.

[0123] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape, consisting of a plano-convex first lens L1 on the object side and a hemispherical second lens L2 on the image side. The second and third optical elements G2 and G3 are both positive power lenses, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 on the object side and a positive power ninth lens L9 on the image side. The sixth optical element G6 is a cemented doublet, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublet groups. The tenth optical element G10 is a meniscus-shaped twelfth lens L12 with a concave image side. The seventh cemented doublet group G7 is a cemented doublet, consisting of a thirteenth lens L13 with positive optical power on the object side and a fourteenth lens L14 with negative optical power on the image side. The eighth cemented doublet group G8 is a cemented doublet, consisting of a fifteenth lens L15 with negative optical power on the object side and a sixteenth lens L16 with positive optical power on the image side. The eighth cemented doublet group G8 and the seventh cemented doublet group G7 form two symmetrical cemented doublet groups. The ninth optical element G9 is a seventeenth lens L17.

[0124] In this embodiment, the system focal length is 1.8 mm, the working distance is 0.17 mm, the numerical aperture is 1.45, and the lens thickness and radius of the microscope objective are shown in Table 5 below:

[0125]

[0126]

[0127] Table 5

[0128] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0129] Figure 17 This is a lateral aberration diagram of the microscope objective lens in the fourth embodiment, where 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.

[0130] Figure 18 This is a lateral aberration diagram of the microscope objective lens in the fourth embodiment, with a scale bar of ±5 micrometers. As can be seen from the diagram, the curve is close to the horizontal axis, indicating good imaging performance.

[0131] Figure 19 This is a field curvature distortion diagram of the microscope objective lens according to the fourth embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units 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 less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, the vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 2μm and a minimum value of -2μm. The right figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 0.5%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 0.5% and a minimum of -0.5%.

[0132] Figure 20 This is a chromatic aberration curve of the microscope objective lens according to the fourth embodiment. The chromatic aberration correction is good across the entire wavelength, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0133] The objective lens of the biological fluorescence microscope in this embodiment has a large numerical aperture (NA = 1.45), and in some preferred embodiments the numerical aperture can be greater than 1.5.

[0134] Fifth implementation method

[0135] See Figure 21 In this embodiment, the microscope objective consists of 16 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S25.

[0136] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape, consisting of a plano-convex first lens L1 on the object side and a hemispherical second lens L2 on the image side. The second and third optical elements G2 and G3 are both positive power lenses, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 on the object side and a positive power ninth lens L9 on the image side. The sixth optical element G6 is a cemented doublet group, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublet groups. The seventh cemented doublet group G7 is a cemented doublet group, consisting of a twelfth lens L12 with positive optical power on the object side and a thirteenth lens L13 with negative optical power on the image side. The eighth cemented doublet group G8 is a cemented doublet group, consisting of a fourteenth lens L14 with negative optical power on the object side and a fifteenth lens L15 with positive optical power on the image side. The eighth cemented doublet group G8 and the seventh cemented doublet group G7 form two symmetrical cemented doublet groups. The ninth optical element is the sixteenth lens L16.

[0137] In this embodiment, the system focal length is 1.8 mm, the working distance is 0.17 mm, the numerical aperture is 1.47, and the lens thickness and radius of the microscope objective are shown in Table 6 below:

[0138] surface Radius (mm) Thickness (mm) Nd Vd S25 -54.127 3 1.43 95 S24 -18.655 0.15 S23 6.457 4.5 1.74 32.3 S22 48.001 1 1.60 65.4 S21 2.953 2 S20 -2.548 1.5 1.74 32.3 S19 -163.807 5 1.57 71.3 S18 -4.598 0.15 S17 -45.323 2 1.43 95 S16 7.548 6 1.74 32.3 S15 -18.729 0.15 S14 -17.561 5.9 1.43 95 S13 78.095 0.15 1.61 44.3 S12 -9.147 7.1 S11 -18.955 2 1.43 95 S10 17.721 0.15 1.61 44.3 S9 -10.995 8.8 1.43 95 S8 15.787 1.5 S7 23.659 7.5 1.43 95 S6 -888.194 0.15 S5 14.523 3 1.43 95 S4 45.156 0.15 S3 3.275 3.98 1.88 40.8 S2 2.565 0.56 1.52 64.1 S1 Infinity 0.17

[0139] Table 6

[0140] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0141] Figure 22 This is a lateral aberration diagram of the microscope objective lens in the fifth embodiment, where the horizontal axes 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.

[0142] Figure 23 This is a lateral aberration diagram of the microscope objective lens in the fifth embodiment, with a scale bar of ±5 micrometers. As can be seen from the diagram, the curve is close to the horizontal axis, indicating good imaging performance.

[0143] Figure 24 This is a field curvature distortion diagram of the microscope objective lens according to the fifth embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units 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 less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, the vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 2μm and a minimum value of -2μm. The right figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 0.2%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 0.2% and a minimum of -0.2%.

[0144] Figure 25 This is a chromatic aberration curve of the microscope objective lens according to the fifth embodiment. The chromatic aberration correction is good across the entire wavelength, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0145] The objective lens of the biological fluorescence microscope in this embodiment has a large numerical aperture (NA = 1.47), and in some preferred embodiments the numerical aperture can be greater than 1.5.

[0146] Sixth implementation method

[0147] See Figure 26 In this embodiment, the microscope objective consists of 18 lenses, with the first surface of the first lens being S1 and the surface of the last lens being S28.

[0148] The first optical element G1 is a cemented lens assembly with positive power and a plano-convex shape, consisting of a plano-convex first lens L1 on the object side and a hemispherical second lens L2 on the image side. The second and third optical elements G2 and G3 are both positive power lenses, namely the third lens L3 and the fourth lens L4. The fourth optical element G4 is a cemented triplet assembly, consisting of two positive power lenses and one negative power lens, namely the fifth lens L5, the sixth lens L6, and the seventh lens L7. The two positive power lenses can be made of the same or different materials, both being low-dispersion materials. The fifth optical element G5 is a cemented doublet assembly, consisting of a negative power eighth lens L8 on the object side and a positive power ninth lens L9 on the image side. The sixth optical element G6 is a cemented doublet, consisting of a tenth lens L10 with positive optical power on the object side and an eleventh lens L11 with negative optical power on the image side. The sixth optical element G6 and the fifth optical element G5 form two symmetrical cemented doublets. The tenth optical element G10 is a meniscus-shaped twelfth lens L12 with a concave image side. The seventh cemented doublet G7 is a cemented doublet, consisting of a thirteenth lens L13 with positive optical power on the object side and a fourteenth lens L14 with negative optical power on the image side. The eighth cemented doublet G8 is a cemented doublet, consisting of a fifteenth lens L15 with negative optical power on the object side and a sixteenth lens L16 with positive optical power on the image side. The eighth cemented doublet G8 and the seventh cemented doublet G7 form two symmetrical cemented doublets. The ninth optical element G9 is a positive optical power cemented doublet, consisting of the seventeenth lens L17 located on the object side and the eighteenth lens L18 located on the image side.

[0149] In this embodiment, the system focal length is 4.5 mm, the working distance is 0.17 mm, the numerical aperture is 1.21, and the lens thickness and radius of the microscope objective are shown in Table 7 below:

[0150]

[0151]

[0152] Table 7

[0153] Here, radius refers to the radius of curvature of the surface, and thickness refers to 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 may be the axial thickness of the medium or lens, or it may be the axial air gap between them.

[0154] Figure 27 This is a lateral aberration diagram of the microscope objective lens in the sixth embodiment, where 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.

[0155] Figure 28 This is a lateral aberration diagram of the microscope objective lens in the sixth embodiment, with a scale bar of ±5 micrometers. As can be seen from the diagram, the curve is close to the horizontal axis, indicating good imaging performance.

[0156] Figure 29 This is a field curvature distortion diagram of the microscope objective lens according to the sixth embodiment. The left image is the field curvature diagram, where the vertical axis represents the field of view and the horizontal axis represents the field curvature, with units of 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 less than 2λ / NA. 2 The theoretical values ​​meet the requirement of full-field sharpness and a field-plan objective. In the figure, the vertical axis represents the normalized field of view; the horizontal axis represents the field curvature, with a maximum value of 10 μm and a minimum value of -10 μm. The right figure is a distortion diagram, where the vertical axis represents the field of view and the horizontal axis represents the distortion (percentage). As shown in the figure, the full-field distortion is less than 0.5%. The vertical axis in the figure represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 0.5% and a minimum of -0.5%.

[0157] Figure 30 This is the chromatic aberration curve of the microscope objective lens according to the sixth embodiment. The chromatic aberration correction of the full wavelength curve is good, and the difference between any two curves at each field of view is less than λ / NA2.

[0158] The objective lens of the biological fluorescence microscope in this embodiment has a large object-side field of view (0.625 mm), and in some preferred embodiments the object-side field of view can be greater than 0.65 mm.

[0159] The above description is merely one embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A microscope objective, comprising a first lens group (T1) having positive optical power, a second lens group (T2) having positive optical power, and a third lens group (T3) having negative optical power, arranged sequentially along the optical axis from the object side to the image side, characterized in that, The third lens group (T3) includes a double Gaussian structure consisting of two optical elements; The third lens group (T3) includes a seventh cemented lens group (G7) and an eighth cemented lens group (G8) arranged sequentially from the object side along the optical axis with symmetrical positive and negative optical power. The concave surfaces of the seventh cemented lens group (G7) and the eighth cemented lens group (G8) face each other, forming a double Gaussian structure; The seventh cemented lens group (G7) and the eighth cemented lens group (G8) are each double cemented lens groups; The seventh cemented lens group (G7) consists of a positive power lens on the object side and a negative power lens on the image side. The eighth cemented lens group (G8) consists of a negative power lens on the object side and a positive power lens on the image side. The projection height H2 of the peripheral light rays of the central field of view on the last lens surface of the second lens group (T2) satisfies the following relationship with the lowest projection height H1 of the peripheral light rays of the central field of view on the lens surface of the third lens group (T3) and the projection height H3 of the peripheral light rays of the central field of view on the last lens surface of the first lens group (T1): 0.1 < |H2 / H3| < 1.5; 0.1 < |H1 / H2| < 0.8; The focal length fL1 and the radius RL1 of the first lens of the first lens group (T1) satisfy the following relationship with the focal length fobj of the microscope objective: 1 < |fL1 / fobj|; |RL1 / fobj| = ∞.

2. The microscope objective according to claim 1, characterized in that, Along the optical axis from the object side to the image side, the first lens group (T1) includes a first optical element (G1), a second optical element (G2) and a third optical element (G3), and the second lens group (T2) includes a fourth optical element (G4), a fifth optical element (G5) and a sixth optical element (G6).

3. The microscope objective according to claim 2, characterized in that, The first optical element (G1) is a cemented lens assembly with positive optical power; The object side of the first optical element (G1) is a plane, and the image side is a hemispherical surface.

4. The microscope objective according to claim 3, characterized in that, The first optical element (G1) consists of a plano-convex lens on the object side and a super-hemispherical lens on the image side.

5. The microscope objective according to claim 2, characterized in that, The second optical element (G2) and the third optical element (G3) are each a lens, both having positive optical power.

6. The microscope objective according to claim 2, characterized in that, The fourth optical element (G4) is a triple-colloidal lens assembly; Both the fifth optical element (G5) and the sixth optical element (G6) are cemented doublets and have symmetrical optical power. The fourth optical element (G4), the fifth optical element (G5), and the sixth optical element (G6) have biconvex shapes.

7. The microscope objective according to claim 6, characterized in that, The fourth optical element (G4) consists of two positive power lenses and one negative power lens, and the two positive power lenses are made of materials with an Abbe number greater than 70. The fifth optical element (G5) consists of a negative power lens on the object side and a positive power lens on the image side. The sixth optical element (G6) consists of a positive power lens on the object side and a negative power lens on the image side.

8. The microscope objective according to claim 1, characterized in that, The third lens group (T3) also includes a ninth optical element (G9) of positive power located on the image side of the eighth cemented lens group (G8), wherein the ninth optical element (G9) is a lens or a cemented doublet.

9. The microscope objective according to claim 1, characterized in that, The third lens group (T3) also includes a tenth optical element (G10) with positive or negative optical power located on the object side of the seventh cemented lens group (G7). The tenth optical element (G10) is a lens with a meniscus shape and a concave image side.

10. The microscope objective according to claim 1, characterized in that, The distance D from the object surface to the last surface of the microscope objective and the focal length fobj of the microscope objective satisfy the following relationship: 10 <D / fobj<36.2; The focal length fobj of the microscope objective lens satisfies the following condition: fobj > 1.7; The objective lens's numerical aperture NA satisfies the following condition: 1 <NA<1.5。 11. The microscope objective according to claim 1, characterized in that, The combined focal length fT1 of the first lens group (T1) and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT1 / fobj| < 30.

12. The microscope objective according to claim 1, characterized in that, The combined focal length fT2 of the second lens group (T2) and the focal length fobj of the microscope objective satisfy the following relationship: 1 < |fT2 / fobj|.

13. The microscope objective according to claim 1, characterized in that, The combined focal length fT3 of the third lens group (T3) and the focal length fobj of the microscope objective satisfy the following relationship: 0.1 < |fT3 / fobj|.

14. The microscope objective according to claim 1, characterized in that, It is used for biological fluorescence observation, with a maximum field of view of 30 and an application wavelength of 436-656nm.

Images