microscope objectives

Abstract

This invention relates to a microscope objective, comprising: a first lens group (T1), 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 image side to the object side. The first lens group (T1) has negative optical power; the first lens group (T1) includes at least one single lens and one cemented lens group; the second lens group (T2) includes at least two cemented lens groups; and the third lens group (T3) includes at least two single lenses with positive optical power. In this invention, the microscope objective has a maximum object-side numerical aperture of 1.5, a maximum field of view of 30 mm, chromatic aberration correction in the 400 nm–1000 nm wavelength range, and ensures good fluorescence performance.

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 development trend of microscope objectives is towards larger fields of view and larger apertures (NA). Achieving large numerical aperture apochromatic microscope objectives while ensuring good fluorescence performance and good manufacturability is crucial for the production of large numerical aperture microscope objectives. However, the correction band of commonly used apochromatic objective imaging systems is currently limited to the visible light range of 436 nm to 656 nm, with numerical apertures of 0.1 to 1.4. With the ever-increasing demands for observation resolution, imaging speed, large field of view observation, and observation of special samples in the life sciences and industrial fields, higher requirements are being placed on the operating band, numerical aperture, and observation field of view of objectives. Summary of the Invention

[0003] Based on the problems existing in the prior art, the purpose of this invention is to provide a microscope objective with a numerical aperture of up to 1.5 and a field of view of up to 30 mm, which has chromatic aberration correction in the 400 nm to 1000 nm band and ensures good fluorescence performance.

[0004] To achieve the above-mentioned objective, the present invention provides a microscope objective, comprising: a first lens group, a second lens group having positive optical power, and a third lens group having negative optical power arranged sequentially along the optical axis from the image side to the object side; characterized in that the first lens group has negative optical power.

[0005] The first lens group includes at least one single lens and one cemented lens group;

[0006] The second lens group comprises at least two cemented lens groups;

[0007] The third lens group comprises at least two single lenses with positive optical power.

[0008] According to one aspect of the invention, along the optical axis from the image side to the object side, the first lens group sequentially includes a first lens, a second lens, a first cemented lens group, and a second cemented lens group.

[0009] The first lens and the second cemented lens assembly have positive optical power;

[0010] The second lens and the first cemented lens assembly have negative optical power.

[0011] According to one aspect of the present invention, the first cemented lens assembly is composed of a third lens and a fourth lens cemented together, wherein the third lens has negative optical power and the fourth lens has positive optical power;

[0012] The second cemented lens assembly is composed of a fifth lens and a sixth lens cemented together, wherein the fifth lens has negative optical power and the sixth lens has positive optical power.

[0013] According to one aspect of the invention, the first lens is a convex-concave lens and the second lens is a biconcave lens along the optical axis from the image side to the object side.

[0014] According to one aspect of the invention, along the optical axis from the image side to the object side, the second lens group sequentially includes a third cemented lens group and a fourth cemented lens group.

[0015] The third cemented lens group is composed of a seventh lens, an eighth lens, and a ninth lens cemented together.

[0016] The fourth cemented lens group is composed of the tenth lens, the eleventh lens, and the twelfth lens cemented together.

[0017] According to one aspect of the invention, the seventh lens, the ninth lens, and the eleventh lens have negative optical power;

[0018] The eighth lens, the tenth lens, and the twelfth lens have positive optical power.

[0019] According to one aspect of the invention, the eighth lens, the tenth lens, and the twelfth lens are made of a low-dispersion material.

[0020] According to one aspect of the invention, along the optical axis from the image side to the object side, the third lens group sequentially includes a thirteenth lens, a fourteenth lens, and a fifteenth lens, wherein the thirteenth lens, the fourteenth lens, and the fifteenth lens have positive optical power.

[0021] According to one aspect of the invention, the object-side surface of the fourteenth lens is concave;

[0022] The object side of the fifteenth lens is a plane, and the image side is a hemispherical surface.

[0023] According to one aspect of the invention, along the optical axis from the image side to the object side, the first lens group sequentially includes a first cemented lens group, a third lens, a second cemented lens group, and a sixth lens.

[0024] The third lens and the sixth lens have negative optical power.

[0025] According to one aspect of the present invention, the first cemented lens assembly is composed of a first lens and a second lens cemented together, the first lens having positive optical power and the second lens having negative optical power;

[0026] The second cemented lens assembly is composed of a fourth lens and a fifth lens cemented together, wherein the fourth lens has negative optical power and the fifth lens has positive optical power.

[0027] According to one aspect of the present invention, the image-side surface of the first lens is convex, the object-side surface of the second lens is concave, the image-side surface of the fourth lens is concave, and the object-side surface of the fifth lens is convex.

[0028] According to one aspect of the invention, along the optical axis from the image side to the object side, the second lens group sequentially includes a third cemented lens group, a fourth cemented lens group, and a fifth cemented lens group.

[0029] The third cemented lens group is composed of a seventh lens and an eighth lens cemented together;

[0030] The fourth cemented lens group is composed of the ninth lens, the tenth lens, and the eleventh lens cemented together.

[0031] The fifth cemented lens group is composed of the twelfth lens, the thirteenth lens, and the fourteenth lens cemented together.

[0032] According to one aspect of the invention, the seventh lens, the twelfth lens, and the fourteenth lens have negative optical power;

[0033] The eighth lens and the thirteenth lens have positive optical power;

[0034] Of the ninth, tenth, and eleventh lenses, two lenses have positive optical power and one lens has negative optical power.

[0035] According to one aspect of the invention, both the lens with positive optical power in the fourth cemented lens group and the thirteenth lens are made of low dispersion material.

[0036] According to one aspect of the invention, the eighth lens is a biconvex lens, and the image-side surface of the seventh lens is convex.

[0037] According to one aspect of the invention, along the optical axis from the image side to the object side, the third lens group sequentially includes a fifteenth lens, a sixteenth lens, and a sixth cemented lens group.

[0038] The sixth cemented lens group is composed of the seventeenth lens and the eighteenth lens cemented together.

[0039] According to one aspect of the invention, the fifteenth lens, the sixteenth lens, the seventeenth lens, and the eighteenth lens have positive optical power.

[0040] According to one aspect of the invention, the fifteenth lens and the sixteenth lens are biconvex lenses along the optical axis from the image side to the object side;

[0041] The seventeenth lens is a super-hemispherical lens;

[0042] The eighteenth lens is a plano-convex lens.

[0043] According to one aspect of the invention, along the optical axis from the image side to the object side, the first lens group sequentially includes a first lens, a second lens, and a first cemented lens group.

[0044] The first lens has positive optical power;

[0045] The second lens has negative optical power.

[0046] According to one aspect of the invention, the first lens is a convex-concave lens and the second lens is a biconcave lens along the optical axis from the image side to the object side.

[0047] According to one aspect of the invention, the first cemented lens assembly is composed of a third lens and a fourth lens cemented together, wherein the third lens has negative optical power and the fourth lens has positive optical power.

[0048] According to one aspect of the invention, the image-side surface of the third lens is concave, and the object-side surface of the fourth lens is convex.

[0049] According to one aspect of the invention, along the optical axis from the image side to the object side, the second lens group sequentially includes a second cemented lens group, a third cemented lens group, and a fourth cemented lens group.

[0050] The second cemented lens assembly consists of a fifth lens and a sixth lens cemented together;

[0051] The third cemented lens group is composed of a seventh lens, an eighth lens, and a ninth lens cemented together.

[0052] The fourth cemented lens group is composed of the tenth lens, the eleventh lens, and the twelfth lens cemented together.

[0053] According to one aspect of the invention, the fifth lens, the tenth lens, and the twelfth lens have negative optical power;

[0054] The sixth lens and the eleventh lens have positive optical power;

[0055] Of the seventh lens, the eighth lens, and the ninth lens, two lenses have positive optical power, and one lens has negative optical power.

[0056] According to one aspect of the invention, both the lens with positive optical power in the third cemented lens group and the eleventh lens are made of low dispersion material.

[0057] According to one aspect of the invention, along the optical axis from the image side to the object side, the third lens group sequentially comprises a thirteenth lens, a fourteenth lens, and a fifth cemented lens group.

[0058] The fifth cemented lens group is composed of the cemented fifteenth lens and the sixteenth lens.

[0059] According to one aspect of the invention, the thirteenth lens, the fourteenth lens, the fifteenth lens, and the sixteenth lens have positive optical power.

[0060] According to one aspect of the invention, the thirteenth lens and the fourteenth lens are biconvex lenses along the optical axis from the image side to the object side;

[0061] The fifteenth lens is a super-hemispherical lens;

[0062] The sixteenth lens is a plano-convex lens.

[0063] According to one aspect of the invention, along the optical axis from the image side to the object side, the first lens group sequentially includes a first lens, a first cemented lens group, a second cemented lens group, and a third cemented lens group.

[0064] The first lens has positive optical power.

[0065] According to one aspect of the invention, the first lens is a concave-convex lens along the optical axis from the image side to the object side.

[0066] According to one aspect of the present invention, the first cemented lens assembly is composed of a second lens and a third lens cemented together, the second lens having positive optical power and the third lens having negative optical power;

[0067] The second cemented lens assembly is composed of a fourth lens and a fifth lens cemented together, wherein the fourth lens has negative optical power and the fifth lens has positive optical power;

[0068] The third cemented lens group is composed of a sixth lens and a seventh lens cemented together. The sixth lens has negative optical power, and the seventh lens has positive optical power.

[0069] According to one aspect of the present invention, the image-side surface of the second lens is convex, the object-side surface of the third lens is concave, the image-side surface of the fourth lens is concave, the object-side surface of the fifth lens is convex, and the seventh lens is a biconvex lens.

[0070] According to one aspect of the invention, along the optical axis from the image side to the object side, the second lens group sequentially includes a fourth cemented lens group and a fifth cemented lens group.

[0071] The fourth cemented lens group is composed of an eighth lens, a ninth lens, and a tenth lens cemented together.

[0072] The fifth cemented lens group is composed of the eleventh lens, the twelfth lens, and the thirteenth lens cemented together.

[0073] According to one aspect of the invention, two of the eighth, ninth, and tenth lenses have positive optical power, and one lens has negative optical power.

[0074] The eleventh and thirteenth lenses have negative optical power, and the twelfth lens has positive optical power.

[0075] According to one aspect of the invention, both the lens with positive optical power in the fourth cemented lens group and the twelfth lens are made of low dispersion material.

[0076] According to one aspect of the invention, along the optical axis from the image side to the object side, the third lens group sequentially includes a fourteenth lens, a fifteenth lens, and a sixth cemented lens group.

[0077] The sixth cemented lens group is composed of the sixteenth lens and the seventeenth lens cemented together.

[0078] According to one aspect of the invention, the fourteenth lens, the fifteenth lens, the sixteenth lens, and the seventeenth lens have positive optical power.

[0079] According to one aspect of the invention, the fourteenth lens is a biconvex lens along the optical axis from the image side to the object side;

[0080] The fifteenth lens is a convex-concave lens;

[0081] The sixteenth lens is a super-hemispherical lens;

[0082] The seventeenth lens is a plano-convex lens.

[0083] According to one aspect of the invention, the distance D from the object side to the last surface of the microscope objective and the focal length fobj of the microscope objective satisfy the condition: 10 <D / fobj<40。

[0084] According to one aspect of the invention, the focal length fobj of the microscope objective satisfies the condition: fobj>1.5.

[0085] According to one aspect of the invention, the object-side numerical aperture NA of the microscope objective lens satisfies the condition: 1 <NA<1.52。

[0086] According to one aspect of the invention, the lowest projection height H1 of the central field-of-view edge ray on the lens surface of the third lens group, the projection height H3 of the central field-of-view edge ray on the last lens surface of the first lens group, and the highest projection height H2 of the central field-of-view edge ray on the lens surface of the second lens group respectively satisfy the following conditions: 0.1 < |H1 / H2| < 1; 0.5 < |H2 / H3| < 3.

[0087] According to one aspect of the present invention, the focal length fL1 of the first lens of the first lens group, the radius value RL1 of the image side surface of the first lens of the first lens group, and the focal length fobj of the microscope objective lens satisfy the following conditions: 3<|fL1 / fobj|<20; 1<|RL1 / fobj|<7.

[0088] According to one aspect of the invention, the focal length fT1 of the first lens group and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT1 / fobj| < 20.

[0089] According to one aspect of the invention, the focal length fT2 of the second lens group and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT2 / fobj| < 15.

[0090] According to one aspect of the invention, the focal length fT3 of the third lens group and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT3 / fobj| < 2.5.

[0091] According to the present invention, the microscope objective lens mainly comprises first, second, and third lens groups with optical powers sequentially from the image side to be negative, positive, and negative, respectively. The first lens group includes at least one single lens and one cemented lens group, providing optical power and reducing the numerical aperture for the other lens groups, correcting distortion and field curvature. The second lens group includes at least two cemented lens groups, primarily used for correcting chromatic aberration. The third lens group includes at least two single lenses with positive optical power, providing both optical power and a large numerical aperture, and used for correcting field curvature.

[0092] The chromatic aberration correction of this apochromatic microscope objective imaging system operates within a spectral range of 400 nm to 1000 nm, while maintaining excellent fluorescence performance. The optimal imaging effect is achieved in the 436–656 nm band. Through segmented control of the near-infrared band, the numerical aperture is significantly expanded, reaching up to 1.5, resulting in better sample resolution and effectively enhancing the microscope objective's potential for ultra-high resolution imaging. To further increase the observable area at any given time and expand the object-side field of view, making it easier to locate the desired observation points, the microscope objective boasts a field of view of up to 30 mm. Simultaneously, the wide-spectrum design enables the objective to observe specialized samples. Attached Figure Description

[0093] 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.

[0094] Figure 1 A schematic diagram illustrating the optical structure of a microscope objective lens according to Embodiment 1 of the present invention;

[0095] Figure 2 This schematic diagram illustrates the lateral aberration at zero field of view of the microscope objective lens according to Embodiment 1 of the present invention.

[0096] Figure 3 This schematic diagram illustrates the lateral aberration of the microscope objective lens in Embodiment 1 of the present invention.

[0097] Figure 4 This diagram schematically illustrates the field curvature distortion of a microscope objective lens according to Embodiment 1 of the present invention.

[0098] Figure 5 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to Embodiment 1 of the present invention;

[0099] Figure 6 A schematic diagram illustrating the optical structure of a microscope objective lens according to Embodiment 2 of the present invention;

[0100] Figure 7 This schematic diagram illustrates the lateral aberration at zero field of view of the microscope objective lens according to Embodiment 2 of the present invention.

[0101] Figure 8 This schematic diagram illustrates the lateral aberration of the microscope objective lens in Embodiment 2 of the present invention.

[0102] Figure 9 This diagram schematically illustrates the field curvature distortion of the microscope objective lens according to Embodiment 2 of the present invention.

[0103] Figure 10 A schematic diagram illustrating the chromatic aberration curve of the microscope objective lens according to Embodiment 2 of the present invention;

[0104] Figure 11 A schematic diagram illustrating the optical structure of a microscope objective lens according to Embodiment 3 of the present invention;

[0105] Figure 12 This schematic diagram illustrates the lateral aberration at zero field of view of the microscope objective lens according to Embodiment 3 of the present invention.

[0106] Figure 13 This schematic diagram illustrates the lateral aberration of the microscope objective lens in Embodiment 3 of the present invention.

[0107] Figure 14 This diagram schematically illustrates the field curvature distortion of the microscope objective lens according to Embodiment 3 of the present invention.

[0108] Figure 15 A schematic diagram illustrating the chromatic aberration curve of a microscope objective lens according to Embodiment 3 of the present invention;

[0109] Figure 16 A schematic diagram illustrating the optical structure of a microscope objective lens according to Embodiment 4 of the present invention;

[0110] Figure 17 This schematic diagram illustrates the lateral aberration at zero field of view of the microscope objective lens according to Embodiment 4 of the present invention.

[0111] Figure 18 This schematic diagram illustrates the lateral aberration of the microscope objective lens in Embodiment 4 of the present invention.

[0112] Figure 19 This diagram schematically illustrates the field curvature distortion of the microscope objective lens according to Embodiment 4 of the present invention.

[0113] Figure 20 The diagram illustrates the chromatic aberration curve of the microscope objective lens according to Embodiment 4 of the present invention. Detailed Implementation

[0114] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0115] The description of the embodiments herein, including any references to directions and orientations, is for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0116] like Figure 1 , Figure 6 , Figure 11 or Figure 16 As shown, this embodiment of the invention provides a microscope objective lens, which, along the optical axis from the image side to the object side, sequentially includes: a first lens group T1 with negative optical power, a second lens group T2 with positive optical power, and a third lens group T3 with negative optical power. The first lens group T1 includes at least one single lens and one cemented lens group, providing optical power and reducing the numerical aperture for the other lens groups, correcting distortion and field curvature. The second lens group T2 includes at least two cemented lens groups, mainly used for correcting chromatic aberration. The third lens group T3 includes at least two single lenses with positive optical power, providing both optical power and a large numerical aperture, and used for correcting field curvature. This microscope objective lens is an infinity conjugate objective lens. In this embodiment of the invention, the medium between the observed object and the objective lens can be air or a liquid. When the medium is air, the numerical aperture is less than 1; when the medium is a liquid, its numerical aperture can reach its maximum value.

[0117] In some embodiments of the present invention, such as Figure 1 As shown, along the optical axis from the image side to the object side, the first lens group T1 sequentially includes a first lens 1, a second lens 2, a first cemented lens group G1, and a second cemented lens group G2. The first lens 1 and the second cemented lens group G2 have positive optical power, while the second lens 2 and the first cemented lens group G1 have negative optical power. The surface of the first lens 1 away from the object side is convex, and its concave surface faces the object side. The second lens 2 is a biconcave lens.

[0118] The first cemented lens group G1 is composed of a third lens 3 and a fourth lens 4 cemented together, forming a cemented doublet. The third lens 3 is a negative power lens, and the fourth lens 4 is a positive power lens. The second cemented lens group G2 is composed of a fifth lens 5 and a sixth lens 6 cemented together, forming a cemented doublet. The fifth lens 5 is a negative power lens, and the sixth lens 6 is a positive power lens.

[0119] Along the optical axis from the image side to the object side, the second lens group T2 sequentially includes a third cemented lens group G3 and a fourth cemented lens group G4. The third cemented lens group G3 is composed of the seventh lens 7, the eighth lens 8, and the ninth lens 9 cemented together, forming a three-cemented lens group. The fourth cemented lens group G4 is composed of the tenth lens 10, the eleventh lens 11, and the twelfth lens 12 cemented together, also forming a three-cemented lens group. The seventh lens 7, the ninth lens 9, and the eleventh lens 11 are all negative power lenses, while the eighth lens 8, the tenth lens 10, and the twelfth lens 12 are all positive power lenses. Furthermore, the eighth lens 8, the tenth lens 10, and the twelfth lens 12 are made of low-dispersion materials. In other words, the positive power lenses in the third cemented lens group G3 and the fourth cemented lens group G4 are made of low-dispersion materials.

[0120] Along the optical axis from the image side to the object side, the third lens group T3 sequentially includes three single lenses: the thirteenth lens 13, the fourteenth lens 14, and the fifteenth lens 15, all of which are positive power lenses. The concave surface of the fourteenth lens 14 faces the object side. The surface of the fifteenth lens 15 closest to the object side is planar, while its surface furthest from the object side is a hemispherical surface.

[0121] In some embodiments of the present invention, such as Figure 6 As shown, along the optical axis from the image side to the object side, the first lens group T1 sequentially includes a first cemented lens group G1, a third lens 3, a second cemented lens group G2, and a sixth lens 6. Both the third lens 3 and the sixth lens 6 are negative power lenses. The first cemented lens group G1 is composed of the cemented first lens 1 and the second lens 2, forming a cemented doublet. The first lens 1 is a positive power lens, and the second lens 2 is a negative power lens. The second cemented lens group G2 is composed of the cemented fourth lens 4 and the fifth lens 5, also forming a cemented doublet. The fourth lens 4 is a negative power lens, and the fifth lens 5 is a positive power lens. Regarding the lens shapes, the surface of the first lens 1 away from the object side is convex, the surface of the second lens 2 near the object side is concave, the surface of the fourth lens 4 away from the object side is concave, and the surface of the fifth lens 5 near the object side is convex.

[0122] Along the optical axis from the image side to the object side, the second lens group T2 sequentially includes a third cemented lens group G3, a fourth cemented lens group G4, and a fifth cemented lens group G5. Specifically, the third cemented lens group G3 is composed of the seventh lens 7 and the eighth lens 8 cemented together; the fourth cemented lens group G4 is composed of the ninth lens 9, the tenth lens 10, and the eleventh lens 11 cemented together; and the fifth cemented lens group G5 is composed of the twelfth lens 12, the thirteenth lens 13, and the fourteenth lens 14 cemented together. That is, the third cemented lens group G3 is a cemented-double lens group, while the fourth cemented lens group G4 and the fifth cemented lens group G5 are both cemented-triple lens groups.

[0123] Among them, the seventh lens 7, the twelfth lens 12, and the fourteenth lens 14 are all negative power lenses, while the eighth lens 8 and the thirteenth lens 13 are both positive power lenses. Two of the ninth lens 9, the tenth lens 10, and the eleventh lens 11 are positive power lenses, and the third lens is a negative power lens. Meanwhile, the two positive power lenses in the fourth cemented lens group G4 and the thirteenth lens 13, which also has positive power, all use low-dispersion materials. The specific low-dispersion materials used in the two positive power lenses in the fourth cemented lens group G4 can be the same or different. Regarding lens shape, the eighth lens 8, closer to the object side, is a biconvex lens, and the surface of the seventh lens 7 furthest from the object side is also convex.

[0124] Along the optical axis from the image side to the object side, the third lens group T3 sequentially includes the fifteenth lens 15, the sixteenth lens 16, and the sixth cemented lens group G6. The sixth cemented lens group G6 is a cemented doublet composed of the seventeenth lens 17 and the eighteenth lens 18. The fifteenth lens 15, the sixteenth lens 16, the seventeenth lens 17, and the eighteenth lens 18 are all positive power lenses.

[0125] Along the optical axis from the image side to the object side, the fifteenth lens 15 and the sixteenth lens 16 are both biconvex lenses. In the sixth cemented lens group G6, the seventeenth lens 17, which is far from the object side, is a super-hemispherical lens, and the eighteenth lens 18, which is close to the object side, is a plano-convex lens.

[0126] In some embodiments of the present invention, such as Figure 11 As shown, along the optical axis from the image side to the object side, the first lens group T1 sequentially includes a first lens 1, a second lens 2, and a first cemented lens group G1. The first lens 1 is a positive power lens, and the second lens 2 is a negative power lens. The surface of the first lens 1 near the object side is concave, and its surface away from the object side is convex. The second lens 2 is a biconcave lens. The first cemented lens group G1 is a cemented doublet consisting of a third lens 3 and a fourth lens 4 cemented together. The third lens 3 is a negative power lens, and the fourth lens 4 is a positive power lens. The surface of the third lens 3 away from the object side is concave, and the surface of the fourth lens 4 near the object side is convex.

[0127] Along the optical axis from the image side to the object side, the second lens group T2 sequentially includes a second cemented lens group G2, a third cemented lens group G3, and a fourth cemented lens group G4. Specifically, the second cemented lens group G2 is composed of the cemented fifth lens 5 and the sixth lens 6; the third cemented lens group G3 is composed of the cemented seventh lens 7, the eighth lens 8, and the ninth lens 9; and the fourth cemented lens group G4 is composed of the cemented tenth lens 10, the eleventh lens 11, and the twelfth lens 12. That is, the second cemented lens group G2 is a cemented-double lens group, while the third cemented lens group G3 and the fourth cemented lens group G4 are both cemented-triple lens groups.

[0128] In this group, the fifth lens (5), the tenth lens (10), and the twelfth lens (12) are all negative power lenses, while the sixth lens (6) and the eleventh lens (11) are both positive power lenses. In the third cemented lens group G3, two of the seventh lens (7), the eighth lens (8), and the ninth lens (9) are positive power lenses, and the third lens is a negative power lens. Furthermore, the two positive power lenses in the third cemented lens group G3 and the eleventh lens (11), which also has positive power, all use low-dispersion materials. The specific low-dispersion materials used in the two positive power lenses in the third cemented lens group G3 can be the same or different.

[0129] Along the optical axis from the image side to the object side, the third lens group T3 sequentially includes the thirteenth lens 13, the fourteenth lens 14, and the fifth cemented lens group G5. The fifth cemented lens group G5 is a cemented doublet composed of the fifteenth lens 15 and the sixteenth lens 16. The thirteenth lens 13, fourteenth lens 14, fifteenth lens 15, and sixteenth lens 16 are all positive power lenses. The thirteenth lens 13 and fourteenth lens 14 are both biconvex lenses. In the fifth cemented lens group G5, the fifteenth lens 15, furthest from the object side, is a super-hemispherical lens, and the sixteenth lens 16, closest to the object side, is a plano-convex lens.

[0130] In some embodiments of the present invention, such as Figure 16 As shown, along the optical axis from the image side to the object side, the first lens group T1 sequentially includes a first lens 1, a first cemented lens group G1, a second cemented lens group G2, and a third cemented lens group G3. Among them, the first lens 1 is a positive power convex-concave lens, with its surface near the object side being convex and its surface away from the object side being concave.

[0131] The first cemented lens group G1 is composed of a second lens 2 and a third lens 3 cemented together, wherein the second lens 2 is a positive power lens and the third lens 3 is a negative power lens. In the first cemented lens group G1, the object-side surface of the second lens 2 is convex, and the object-side surface of the third lens 3 is concave. The second cemented lens group G2 is composed of a fourth lens 4 and a fifth lens 5 cemented together, wherein the fourth lens 4 is a negative power lens and the fifth lens 5 is a positive power lens. In the second cemented lens group G2, the object-side surface of the fourth lens 4 is concave, and the object-side surface of the fifth lens 5 is convex. The third cemented lens group G3 is composed of a sixth lens 6 and a seventh lens 7 cemented together, wherein the sixth lens 6 is a negative power lens and the seventh lens 7 is a positive power lens. The object-side surface of the seventh lens 7 in the third cemented lens group G3 is a biconvex lens. That is, the first cemented lens group G1, the second cemented lens group G2, and the third cemented lens group G3 are all double cemented lens groups.

[0132] In the direction from the image side to the object side along the optical axis, the second lens group T2 successively includes a fourth cemented lens group G4 and a fifth cemented lens group G5. Among them, the fourth cemented lens group G4 is composed of an eighth lens 8, a ninth lens 9, and a tenth lens 10 cemented together, and the fifth cemented lens group G5 is composed of an eleventh lens 11, a twelfth lens 12, and a thirteenth lens 13 cemented together. The fourth cemented lens group G4 and the fifth cemented lens group G5 are both triple-cemented lens groups.

[0133] Among the eighth lens 8, the ninth lens 9, and the tenth lens 10 of the fourth cemented lens group G4, two of the lenses are positive-power lenses, and the other lens is a negative-power lens. The eleventh lens 11 and the thirteenth lens 13 of the fifth cemented lens group G5 are both negative-power lenses, and the twelfth lens 12 is a positive-power lens. The two positive-power lenses in the fourth cemented lens group G4 and the positive-power twelfth lens 12 are made of low-dispersion materials. Among them, the specific low-dispersion materials of the two positive-power lenses in the fourth cemented lens group G4 can be the same or different.

[0134] In the direction from the image side to the object side along the optical axis, the third lens group T3 successively includes a fourteenth lens 14, a fifteenth lens 15, and a sixth cemented lens group G6. Among them, the sixth cemented lens group G6 is a doublet lens group composed of a sixteenth lens 16 and a seventeenth lens 17 cemented together. The fourteenth lens 14, the fifteenth lens 15, the sixteenth lens 16, and the seventeenth lens 17 are all positive-power lenses. The fourteenth lens 14 is a biconvex lens. The fifteenth lens 15 is a convex-concave lens, with its object-side surface being concave and its image-side surface being convex. In the direction from the image side to the object side along the optical axis, the sixteenth lens 16, which is farther from the object side in the sixth cemented lens group G6, is a super-hemispherical lens, and the seventeenth lens 17, which is closer to the object side, is a plano-convex lens.

[0135] In the embodiments of the present invention, the distance D from the object side surface of the microscope objective to the last surface and the focal length fobj of the microscope objective satisfy the conditional formula: 10 < D / fobj < 40. Here, the last surface refers to the image-side surface of the first lens 1, which is the lens surface of the microscope objective closest to the image side. The focal length fobj of the microscope objective satisfies the conditional formula: fobj > 1.5. The object-side numerical aperture NA of the microscope objective satisfies the conditional formula: 1 < NA < 1.52. The numerical aperture of the microscope objective is related to the objective focal length. When the entrance pupil is the same, the smaller the focal length, the larger the numerical aperture.

[0136] In the embodiments of the present invention, the lowest projection height H1 of the marginal rays of the central field on the lens surface of the third lens group T3, the projection height H3 of the marginal rays of the central field on the last lens surface of the first lens group T1, and the highest projection height H2 of the marginal rays of the central field on the lens surface of the second lens group T2 respectively satisfy the following conditional formulas: 0.1 < |H1 / H2| < 1; 0.5 < |H2 / H3| < 3.

[0137] In this embodiment of the invention, the focal length fL1 of the first lens of the first lens group T1, the radius RL1 of the image-side surface of the first lens of the first lens group T1, and the focal length fobj of the microscope objective lens satisfy the following conditions: 3 < |fL1 / fobj| < 20; 1 < |RL1 / fobj| < 7. Here, the first lens of the first lens group T1 refers to a single lens or a cemented lens.

[0138] In this embodiment of the invention, the focal length fT1 of the first lens group T1 and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT1 / fobj| < 20. The focal length fT2 of the second lens group T2 and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT2 / fobj| < 15. The focal length fT3 of the third lens group T3 and the focal length fobj of the microscope objective satisfy the condition: 0 < |fT3 / fobj| < 2.5.

[0139] In summary, in some embodiments of the present invention, the spectral range corresponding to the chromatic aberration correction working band of the apochromatic microscope objective imaging system is 400nm to 1000nm, while ensuring good fluorescence performance, with the best imaging effect in the 436-656nm band. Through segmented control of the near-infrared band, the numerical aperture is significantly expanded, reaching up to 1.5, resulting in better sample resolution and effectively enhancing the microscope objective's potential for ultra-high resolution imaging. To further increase the observable area at the same time, expand the object-side field of view, and make it easier to find the desired observation site under a large field of view, the field of view of this microscope objective can reach 30mm. Simultaneously, the wide-spectrum design enables the objective to observe special samples. The working distance of this microscope objective can reach 0.17mm or more, including working distances of 0 to 0.17mm, where the working distance refers to the distance from the coverslip to the edge of the first lens group T1 near the image side.

[0140] The microscope objectives of the present invention will be specifically described below with reference to four embodiments, in conjunction with the accompanying drawings and tables. In the following embodiments, the surfaces of each lens are referred to as S1, S2, ..., SN, and each cemented surface of the cemented lens assembly is denoted as one surface.

[0141] The parameters for each embodiment that meets the above conditions are shown in Table 1 below:

[0142]

[0143]

[0144] Table 1

[0145] Example 1

[0146] like Figure 1 As shown in Table 1, the parameters of the microscope objective lens in this embodiment are as follows:

[0147] The focal length is 1.8mm, the working distance is 0.13mm, the numerical aperture is 1.45, the field of view is 26.5mm, and the spectral range of the working band is 400nm~1000nm.

[0148] In this embodiment, the height of the edge ray in the central field of view reaches its maximum value between the surface of the fourth cemented lens group G4 of the second lens group T2 and the surface of the thirteenth lens 13 of the third lens group T3.

[0149] Table 2 lists the relevant parameters of each lens in the microscope objective of this embodiment, including: radius, thickness, refractive index of the material, and Abbe number. The microscope objective of this embodiment consists of 15 lenses. Starting from the image side, the object side of the first lens 1 is S1, and the image side of the last lens, i.e., the fifteenth lens 15, is S24. Here, the radius refers to the radius of curvature of the lens surface, and the 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.

[0150]

[0151]

[0152] Table 2

[0153] Figure 2 This is a lateral aberration diagram of the microscope objective lens in this embodiment at 0 field of view. The horizontal axes PY and PX represent the normalized entrance pupil size, the vertical axis represents lateral aberration, the scale bar is ±5 micrometers, the Y direction is the meridional direction, and the X direction is the sagittal direction. As shown in the figure, this microscope objective lens has good aberration balance and good imaging performance.

[0154] Figure 3 This is a lateral aberration diagram of the first field of view of the microscope objective lens in this embodiment. The scale bar is ±5 micrometers. As can be seen from the figure, the curve is close to the horizontal axis, indicating that the microscope objective lens has good imaging performance.

[0155] Figure 4 This is a field curvature distortion diagram of the microscope objective lens in this 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. 2The 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, and 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 0.7%. In the figure, the vertical axis represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 1% and a minimum of -1%.

[0156] Figure 5 This is a chromatic aberration curve of the microscope objective lens in this embodiment. The chromatic aberration correction across the entire wavelength is good, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0157] In this embodiment, the objective lens of the biological fluorescence microscope has a large numerical aperture (NA = 1.45), and in some better embodiments, the numerical aperture can be greater than 1.5.

[0158] Example 2

[0159] like Figure 6 As shown in Table 1, the parameters of the microscope objective lens in this embodiment are as follows:

[0160] The focal length is 1.8mm, the working distance is 0.17mm, the numerical aperture is 1.5, the field of view is 30mm, and the spectral range of the working band is 436nm~656nm.

[0161] In this embodiment, the height of the edge ray in the central field of view reaches its maximum value between the sixth lens 6 of the first lens group T1 and the fifth cemented lens group G5 of the second lens group T2.

[0162] Table 3 lists the relevant parameters of each lens in the microscope objective of this embodiment, including: radius, thickness, refractive index of the material, and Abbe number. The microscope objective of this embodiment consists of 18 lenses. Starting from the image side, the object side of the first lens 1 is S1, and the image side of the last lens, the eighteenth lens 18, is S28. Here, the radius refers to the radius of curvature of the lens surface, and the 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.

[0163]

[0164]

[0165] Table 3

[0166] Figure 7This is a lateral aberration diagram of the microscope objective lens in this embodiment at 0 field of view. The horizontal axes PY and PX represent the normalized entrance pupil size, the vertical axis represents lateral aberration, the scale bar is ±5 micrometers, the Y direction is the meridional direction, and the X direction is the sagittal direction. As shown in the figure, this microscope objective lens has good aberration balance and good imaging performance.

[0167] Figure 8 This is a lateral aberration diagram of the first field of view of the microscope objective lens in this embodiment. The scale bar is ±5 micrometers. As can be seen from the figure, the curve is close to the horizontal axis, indicating that the microscope objective lens has good imaging performance.

[0168] Figure 9 This is a field curvature distortion diagram of the microscope objective lens in this 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 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 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%.

[0169] Figure 10 This is a chromatic aberration curve of the microscope objective lens in this embodiment. The chromatic aberration correction across the entire wavelength is good, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0170] In this embodiment, the objective lens of the biological fluorescence microscope has a large object-side field of view (0.13 mm) and a large numerical aperture (NA = 1.5). In some better embodiments, the field of view can be greater than 0.13 mm and the numerical aperture can be greater than 1.5.

[0171] Example 3

[0172] like Figure 11 As shown in Table 1, the parameters of the microscope objective lens in this embodiment are as follows:

[0173] The focal length is 1.81mm, the working distance is 0.15mm, the numerical aperture is 1.44, the field of view is 30mm, and the spectral range of the working band is 400nm~1000nm.

[0174] In this embodiment, the height of the edge rays in the central field of view reaches its maximum value between the first cemented lens group G1 of the first lens group T1 and the fourth cemented lens group G4 of the second lens group T2.

[0175] Table 4 lists the relevant parameters of each lens in the microscope objective of this embodiment, including: radius, thickness, refractive index of the material, and Abbe number. The microscope objective of this embodiment consists of 16 lenses. Starting from the image side, the object side of the first lens 1 is S1, and the image side of the last lens, the sixteenth lens 16, is S25. Here, the radius refers to the radius of curvature of the lens surface, and the 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.

[0176]

[0177]

[0178] Table 4

[0179] Figure 12 This is a lateral aberration diagram of the microscope objective lens in this embodiment at 0 field of view. The horizontal axes PY and PX represent the normalized entrance pupil size, the vertical axis represents lateral aberration, the scale bar is ±5 micrometers, the Y direction is the meridional direction, and the X direction is the sagittal direction. As shown in the figure, this microscope objective lens has good aberration balance and good imaging performance.

[0180] Figure 13 This is a lateral aberration diagram of the first field of view of the microscope objective lens in this embodiment. The scale bar is ±5 micrometers. As can be seen from the figure, the curve is close to the horizontal axis, indicating that the microscope objective lens has good imaging performance.

[0181] Figure 14 This is a field curvature distortion diagram of the microscope objective lens in this 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 requirements for a clear image across the entire field of view, fulfilling the requirements for a field-plan objective lens. In the figure, the vertical axis represents the normalized field of view, and 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 distortion across the entire field of view is less than 1%. In the figure, the vertical axis represents the normalized field of view, and the horizontal axis represents the distortion, with a maximum of 1% and a minimum of -1%.

[0182] Figure 15 This is a chromatic aberration curve of the microscope objective lens in this embodiment. The chromatic aberration correction across the entire wavelength is good, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0183] In this embodiment, the objective lens of the biological fluorescence microscope has a large object-side field of view (0.15 mm) and a large numerical aperture (NA = 1.44).

[0184] Example 4

[0185] like Figure 16 As shown in Table 1, the parameters of the microscope objective lens in this embodiment are as follows:

[0186] The focal length is 1.8mm, the working distance is 0.14mm, the numerical aperture is 1.44, the field of view is 30mm, and the spectral range of the working band is 400nm~1000nm.

[0187] In this embodiment, the height of the edge rays in the central field of view reaches its maximum value between the third cemented lens group G3 of the first lens group T1 and the fifth cemented lens group G5 of the second lens group T2.

[0188] Table 5 lists the relevant parameters of each lens in the microscope objective of this embodiment, including: radius, thickness, refractive index of the material, and Abbe number. The microscope objective of this embodiment consists of 17 lenses. Starting from the image side, the object side of the first lens 1 is S1, and the image side of the last lens, the seventeenth lens 17, is S26. Here, the radius refers to the radius of curvature of the lens surface, and the 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.

[0189]

[0190]

[0191] Table 5

[0192] Figure 17 This is a lateral aberration diagram of the microscope objective lens in this embodiment at 0 field of view. The horizontal axes PY and PX represent the normalized entrance pupil size, the vertical axis represents lateral aberration, the scale bar is ±5 micrometers, the Y direction is the meridional direction, and the X direction is the sagittal direction. As shown in the figure, this microscope objective lens has good aberration balance and good imaging performance.

[0193] Figure 18 This is a lateral aberration diagram of the first field of view of the microscope objective lens in this embodiment. The scale bar is ±5 micrometers. As can be seen from the figure, the curve is close to the horizontal axis, indicating that the microscope objective lens has good imaging performance.

[0194] Figure 19 This is a field curvature distortion diagram of the microscope objective lens in this 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. 2The theoretical values ​​meet the requirements for a clear image across the entire field of view, fulfilling the requirements for a field-plan objective lens. In the figure, the vertical axis represents the normalized field of view, and the horizontal axis represents the field curvature, with a maximum value of 2 μm and a minimum value of -2 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 distortion across the entire field of view 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%.

[0195] Figure 20 This is a chromatic aberration curve of the microscope objective lens in this embodiment. The chromatic aberration correction across the entire wavelength is good, and the difference between any two curves at any field of view is less than λ / NA. 2 .

[0196] In this embodiment, the objective lens of the biological fluorescence microscope has a large numerical aperture (NA = 1.44), and in some better embodiments, the numerical aperture can be greater than 1.5.

[0197] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A microscope objective, comprising: A first lens group (T1), a second lens group (T2) having positive refractive power and a third lens group (T3) having negative refractive power are arranged in order from the image side to the object side along the optical axis, characterized in that the first lens group (T1) has negative refractive power; The first lens group (T1) comprises at least one single lens and one cemented lens group; The second lens group (T2) comprises at least two cemented lens groups; The third lens group (T3) comprises at least two single lenses having positive refractive power; The refractive power arrangement of each lens group includes the following arrangement schemes: Arrangement scheme one, along the optical axis from the image side to the object side, the first lens group (T1) includes a first lens (1), a second lens (2), a first cemented lens group (G1) and a second cemented lens group (G2) in order, the first lens (1) and the second cemented lens group (G2) have positive refractive power; the second lens (2) and the first cemented lens group (G1) have negative refractive power; Arrangement scheme two, along the optical axis from the image side to the object side, the first lens group (T1) includes a first cemented lens group (G1), a third lens (3), a second cemented lens group (G2) and a sixth lens (6) in order, the third lens (3) and the sixth lens (6) have negative refractive power; Arrangement scheme three, along the optical axis from the image side to the object side, the first lens group (T1) includes a first lens (1), a second lens (2) and a first cemented lens group (G1) in order, the first lens (1) has positive refractive power; the second lens (2) has negative refractive power; Arrangement scheme four, along the optical axis from the image side to the object side, the first lens group (T1) includes a first lens (1), a first cemented lens group (G1), a second cemented lens group (G2) and a third cemented lens group (G3) in order, the first lens (1) has positive refractive power.

2. The microscope objective according to claim 1, characterized in that In arrangement scheme one, the first cemented lens group (G1) is composed of a third lens (3) and a fourth lens (4), the third lens (3) has negative refractive power, and the fourth lens (4) has positive refractive power; The second cemented lens group (G2) is composed of a fifth lens (5) and a sixth lens (6), the fifth lens (5) has negative refractive power, and the sixth lens (6) has positive refractive power.

3. The microscope objective according to claim 1, characterized in that In arrangement scheme one, along the optical axis from the image side to the object side, the first lens (1) is a convex-concave lens, and the second lens (2) is a double-concave lens.

4. The microscope objective according to claim 1, characterized in that In arrangement scheme one, along the optical axis from the image side to the object side, the second lens group (T2) includes a third cemented lens group (G3) and a fourth cemented lens group (G4) in order, The third cemented lens group (G3) is composed of a seventh lens (7), an eighth lens (8) and a ninth lens (9); The fourth cemented lens group (G4) is composed of a tenth lens (10), an eleventh lens (11) and a twelfth lens (12).

5. The microscope objective according to claim 4, characterized in that In arrangement scheme one, the seventh lens (7), the ninth lens (9) and the eleventh lens (11) have negative refractive power; The eighth lens (8), the tenth lens (10) and the twelfth lens (12) have positive refractive powers.

6. The microscope objective according to claim 5, characterized in that In the arrangement scheme one, the eighth lens (8), the tenth lens (10) and the twelfth lens (12) adopt low-dispersion materials.

7. The microscope objective according to claim 4, characterized in that In the arrangement scheme one, the third lens group (T3) comprises, in order from the image side to the object side along the optical axis, a thirteenth lens (13), a fourteenth lens (14) and a fifteenth lens (15), and the thirteenth lens (13), the fourteenth lens (14) and the fifteenth lens (15) have positive refractive powers.

8. The microscope objective according to claim 7, characterized in that In the arrangement scheme one, the object side surface of the fourteenth lens (14) is a concave surface. The object side surface of the fifteenth lens (15) is a plane, and the image side surface is a hyper-hemispherical surface.

9. The microscope objective according to claim 1, characterized in that In the arrangement scheme two, the first cemented lens group (G1) is composed of a first lens (1) and a second lens (2) in cementation, the first lens (1) has a positive refractive power, and the second lens (2) has a negative refractive power. The second cemented lens group (G2) is composed of a fourth lens (4) and a fifth lens (5) in cementation, the fourth lens (4) has a negative refractive power, and the fifth lens (5) has a positive refractive power.

10. The microscope objective according to claim 9, characterized in that In the arrangement scheme two, the image side surface of the first lens (1) is a convex surface, the object side surface of the second lens (2) is a concave surface, the image side surface of the fourth lens (4) is a concave surface, and the object side surface of the fifth lens (5) is a convex surface.

11. The microscope objective according to claim 1, characterized in that In the arrangement scheme two, the second lens group (T2) comprises, in order from the image side to the object side along the optical axis, a third cemented lens group (G3), a fourth cemented lens group (G4) and a fifth cemented lens group (G5), The third cemented lens group (G3) is composed of a seventh lens (7) and an eighth lens (8) in cementation. The fourth cemented lens group (G4) is composed of a ninth lens (9), a tenth lens (10) and an eleventh lens (11) in cementation. The fifth cemented lens group (G5) is composed of a twelfth lens (12), a thirteenth lens (13) and a fourteenth lens (14) in cementation.

12. The microscope objective according to claim 11, characterized in that In the arrangement scheme two, the seventh lens (7), the twelfth lens (12) and the fourteenth lens (14) have negative refractive powers. The eighth lens (8) and the thirteenth lens (13) have positive refractive powers. Among the ninth lens (9), the tenth lens (10) and the eleventh lens (11), two lenses have positive refractive powers, and one lens has a negative refractive power.

13. The microscope objective according to claim 12, characterized in that In the arrangement scheme two, the lens with a positive refractive power in the fourth cemented lens group (G4) and the thirteenth lens (13) both adopt low-dispersion materials.

14. The microscope objective according to claim 11, characterized in that In the arrangement scheme two, the eighth lens (8) is a double-convex lens, and the image side surface of the seventh lens (7) is a convex surface.

15. The microscope objective of claim 11, wherein, In the arrangement scheme two, the third lens group (T3) comprises, in order from the image side to the object side along the optical axis, a fifteenth lens (15), a sixteenth lens (16) and a sixth cemented lens group (G6), The sixth cemented lens group (G6) is composed of a seventeenth lens (17) and an eighteenth lens (18) in cementation.

16. The microscope objective according to claim 15, characterized in that In the second arrangement, the fifteenth lens (15), the sixteenth lens (16), the seventeenth lens (17) and the eighteenth lens (18) have positive refractive powers.

17. The microscope objective according to claim 15, characterized in that In the second arrangement, the fifteenth lens (15) and the sixteenth lens (16) are biconvex lenses in the direction from the image side to the object side along the optical axis. The seventeenth lens (17) is a super-hemisphere lens. The eighteenth lens (18) is a plano-convex lens.

18. The microscope objective according to claim 1, characterized in that In the third arrangement, the first lens (1) is a biconvex lens and the second lens (2) is a biconcave lens in the direction from the image side to the object side along the optical axis.

19. The microscope objective according to claim 1, characterized in that In the third arrangement, the first cemented lens group (G1) is composed of the third lens (3) and the fourth lens (4), the third lens (3) has a negative refractive power, and the fourth lens (4) has a positive refractive power.

20. The microscope objective according to claim 19, characterized in that In the third arrangement, the image side surface of the third lens (3) is concave, and the object side surface of the fourth lens (4) is convex.

21. The microscope objective according to claim 1, characterized in that In the third arrangement, the second lens group (T2) sequentially includes a second cemented lens group (G2), a third cemented lens group (G3) and a fourth cemented lens group (G4) in the direction from the image side to the object side along the optical axis, The second cemented lens group (G2) is composed of the fifth lens (5) and the sixth lens (6). The third cemented lens group (G3) is composed of the seventh lens (7), the eighth lens (8) and the ninth lens (9). The fourth cemented lens group (G4) is composed of the tenth lens (10), the eleventh lens (11) and the twelfth lens (12).

22. The microscope objective according to claim 21, characterized in that In the third arrangement, the fifth lens (5), the tenth lens (10) and the twelfth lens (12) have negative refractive powers. The sixth lens (6) and the eleventh lens (11) have positive refractive powers. Two of the seventh lens (7), the eighth lens (8) and the ninth lens (9) have positive refractive powers, and one of them has a negative refractive power.

23. The microscope objective according to claim 22, characterized in that In the third arrangement, the lens with a positive refractive power in the third cemented lens group (G3) and the eleventh lens (11) are both made of low dispersion material.

24. The microscope objective of claim 21, wherein, In the third arrangement, the third lens group (T3) sequentially includes the thirteenth lens (13), the fourteenth lens (14) and a fifth cemented lens group (G5) in the direction from the image side to the object side along the optical axis, The fifth cemented lens group (G5) is composed of the fifteenth lens (15) and the sixteenth lens (16).

25. The microscope objective according to claim 24, characterized in that In the third arrangement, the thirteenth lens (13), the fourteenth lens (14), the fifteenth lens (15) and the sixteenth lens (16) have positive refractive powers.

26. The microscope objective of claim 24, wherein, In the third arrangement, the thirteenth lens (13) and the fourteenth lens (14) are biconvex lenses in the direction from the image side to the object side along the optical axis. The fifteenth lens (15) is a super-hemisphere lens. The sixteenth lens (16) is a plano-convex lens.

27. The microscope objective according to claim 1, characterized in that In the fourth arrangement, the first lens (1) is a biconcave lens in the direction from the image side to the object side along the optical axis.

28. The microscope objective according to claim 1, characterized in that In the fourth arrangement, the first cemented lens group (G1) is composed of a second lens (2) and a third lens (3), the second lens (2) has positive refractive power, and the third lens (3) has negative refractive power; The second cemented lens group (G2) is composed of a fourth lens (4) and a fifth lens (5), the fourth lens (4) has negative refractive power, and the fifth lens (5) has positive refractive power; The third cemented lens group (G3) is composed of a sixth lens (6) and a seventh lens (7), the sixth lens (6) has negative refractive power, and the seventh lens (7) has positive refractive power.

29. The microscope objective according to claim 28, characterized in that In the fourth arrangement, the image side surface of the second lens (2) is a convex surface, the object side surface of the third lens (3) is a concave surface, the image side surface of the fourth lens (4) is a concave surface, the object side surface of the fifth lens (5) is a convex surface, and the seventh lens (7) is a double convex lens.

30. The microscope objective according to claim 1, characterized in that In the fourth arrangement, in the direction from the image side to the object side along the optical axis, the second lens group (T2) sequentially includes a fourth cemented lens group (G4) and a fifth cemented lens group (G5), The fourth cemented lens group (G4) is composed of an eighth lens (8), a ninth lens (9), and a tenth lens (10); The fifth cemented lens group (G5) is composed of an eleventh lens (11), a twelfth lens (12), and a thirteenth lens (13).

31. The microscope objective according to claim 30, characterized in that In the fourth arrangement, two of the eighth lens (8), the ninth lens (9), and the tenth lens (10) have positive refractive power, and one of them has negative refractive power; The eleventh lens (11) and the thirteenth lens (13) have negative refractive power, and the twelfth lens (12) has positive refractive power.

32. The microscope objective according to claim 31, characterized in that In the fourth arrangement, the lens with positive refractive power in the fourth cemented lens group (G4) and the twelfth lens (12) are both made of low dispersion material.

33. The microscope objective of claim 30, wherein, In the fourth arrangement, in the direction from the image side to the object side along the optical axis, the third lens group (T3) sequentially includes a fourteenth lens (14), a fifteenth lens (15), and a sixth cemented lens group (G6), The sixth cemented lens group (G6) is composed of a sixteenth lens (16) and a seventeenth lens (17).

34. The microscope objective according to claim 33, characterized in that In the fourth arrangement, the fourteenth lens (14), the fifteenth lens (15), the sixteenth lens (16), and the seventeenth lens (17) have positive refractive power.

35. The microscope objective of claim 33, wherein, In the fourth arrangement, in the direction from the image side to the object side along the optical axis, the fourteenth lens (14) is a double convex lens; The fifteenth lens (15) is a convex-concave lens; The sixteenth lens (16) is a super-hemisphere lens; The seventeenth lens (17) is a plano-convex lens.

36. The microscope objective according to any one of claims 1 to 35, characterized in that The distance D from the object side surface of the microscope objective to the last surface and the focal length fobj of the microscope objective satisfy the condition formula: 10 < D / fobj < 40.

37. The microscope objective according to any one of claims 1 to 35, characterized in that The focal length fobj of the microscope objective satisfies the condition formula: fobj > 1.

5.

38. The microscope objective according to any one of claims 1 to 35, characterized in that The object side numerical aperture NA of the microscope objective satisfies the condition formula: 1 < NA < 1.

52.

39. The microscope objective according to any one of claims 1 to 35, characterized in that The lowest projection height H1 of the central field of view edge ray on the lens surface of the third lens group (T3), the projection height H3 of the central field of view edge ray on the last lens surface of the first lens group (T1), and the highest projection height H2 of the central field of view edge ray on the lens surface of the second lens group (T2) satisfy the following conditional expressions respectively: 0.1<|H1 / H2|<1; 0.5<|H2 / H3|<3.

40. The microscope objective according to any one of claims 1 to 35, characterized in that The focal length fL1 of the first lens of the first lens group (T1), the radius value RL1 of the image side surface of the first lens of the first lens group (T1), and the focal length fobj of the microscope objective satisfy the following conditional expressions respectively: 3<|fL1 / fobj|<20; 1<|RL1 / fobj|<7.

41. The microscope objective according to any one of claims 1 to 35, characterized in that The focal length fT1 of the first lens group (T1) and the focal length fobj of the microscope objective satisfy the conditional expression: 0<|fT1 / fobj|<20.

42. The microscope objective according to any one of claims 1 to 35, characterized in that The focal length fT2 of the second lens group (T2) and the focal length fobj of the microscope objective satisfy the conditional expression: 0<|fT2 / fobj|<15.

43. The microscope objective according to any one of claims 1 to 35, characterized in that The focal length fT3 of the third lens group (T3) and the focal length fobj of the microscope objective satisfy the conditional expression: 0<|fT3 / fobj|<2.5.

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