Achromatic microscopic tube lens

Abstract

The utility model relates to an achromatic microscopic tube lens, and relates to the technical field of measurement and control instruments in accurate manufacturing. Comprising a first lens group, a second lens group and a sixth lens. The first lens group comprises a first lens and a second lens, and the first lens and the second lens are tightly attached; the second lens group comprises a third lens, a fourth lens and a fifth lens, and the third lens, the fourth lens and the fifth lens are tightly attached in sequence; the first lens group, the second lens group and the sixth lens are sequentially arranged at intervals. The first lens group and the second lens group respectively adopt two groups of combined lenses, namely the first lens and the second lens are tightly attached, and the third lens, the fourth lens and the fifth lens are tightly attached, so that the achromatic and apochromatic effects can be realized, and the first lens group, the second lens group and the sixth lens are sequentially arranged at intervals; through mutual compensation of refractive indexes and dispersion characteristics of different lens groups and lenses, an achromatic effect is realized. The problem that an existing microscopic tube lens is difficult to meet the achromatic requirement in the microscopic technology industry is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of measuring and controlling instruments and meters in precision manufacturing, and in particular to an achromatic microscope tube lens. Background Art

[0002] As an important tool in the fields of scientific research and medicine, the microscope is constantly evolving and improving in terms of its replacement and upgrade. However, its performance directly depends on the core component therein - the microscope tube lens. With the rapid development of microscope technology, more and more application scenarios require the use of achromatic microscope tube lenses to complete high-precision observation and analysis tasks. The microscope tube lenses on the market in the past were difficult to meet these requirements, especially in some high-end application scenarios where higher requirements are placed on imaging quality and accuracy.

[0003] Regarding the above related technologies, there is a problem that the existing microscope tube lenses are difficult to meet the achromatic requirements in the microscope technology industry. Summary of the Utility Model

[0004] In view of the above deficiencies of the existing technology, the purpose of the present utility model is to provide an achromatic microscope tube lens, aiming to solve the problem that the existing microscope tube lenses are difficult to meet the achromatic requirements in the microscope technology industry.

[0005] An achromatic microscope tube lens provided by the present application adopts the following technical solution: An achromatic microscope tube lens, comprising:

[0006] A first lens group, comprising a first lens and a second lens, the first lens and the second lens being closely attached;

[0007] A second lens group, comprising a third lens, a fourth lens and a fifth lens, the third lens, the fourth lens and the fifth lens being closely attached in sequence;

[0008] A sixth lens;

[0009] The first lens group, the second lens group and the sixth lens are arranged at intervals in sequence for mutual compensation to eliminate chromatic aberration.

[0010] Optionally, the distance between the first lens and the diaphragm is 21.8 - 22.2 millimeters;

[0011] The distance between the second lens and the third lens is 4 - 4.4 millimeters;

[0012] The distance between the fifth lens and the sixth lens is 19.6 - 20 millimeters;

[0013] The distance between the sixth lens and the image plane is 21.8 - 22.2 millimeters.

[0014] Optionally, the effective apertures of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all greater than or equal to 17 mm.

[0015] Optionally, the absolute value of the ratio of the first lens group to the lens focal length is greater than 3 and less than 4;

[0016] The ratio of the second lens group to the lens focal length is greater than -8 and less than -5;

[0017] The absolute value of the ratio of the sixth lens to the lens focal length is greater than 2 and less than 3.

[0018] Optionally, the radius of curvature of the surface of the first lens adjacent to the incident light source is greater than or equal to 39 mm and less than or equal to 41 mm;

[0019] The radius of curvature of the surface of the first lens facing away from the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm;

[0020] The radius of curvature of the surface of the second lens adjacent to the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm;

[0021] The radius of curvature of the surface of the second lens facing away from the incident light source is greater than or equal to -208 mm and less than or equal to -206 mm;

[0022] The radius of curvature of the surface of the third lens adjacent to the incident light source is greater than or equal to 35.6 mm and less than or equal to 37.6 mm;

[0023] The radius of curvature of the surface of the third lens facing away from the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm;

[0024] The radius of curvature of the surface of the fourth lens adjacent to the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm;

[0025] The radius of curvature of the surface of the fourth lens facing away from the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm;

[0026] The radius of curvature of the surface of the fifth lens facing the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm;

[0027] The radius of curvature of the surface of the fifth lens facing away from the incident light source is greater than or equal to 16.1 mm and less than or equal to 18.1 mm;

[0028] The radius of curvature of the surface of the sixth lens facing the incident light source is greater than or equal to 28.9 mm and less than or equal to 30.9 mm;

[0029] The radius of curvature of the surface of the sixth lens facing away from the incident light source is greater than or equal to 32.2 mm and less than or equal to 34.2 mm.

[0030] Optionally, the refractive index of the first lens is greater than or equal to 1.48 and less than or equal to 1.52;

[0031] The refractive index of the second lens is greater than or equal to 1.78 and less than or equal to 1.82;

[0032] The refractive index of the third lens is greater than or equal to 1.88 and less than or equal to 1.92;

[0033] The refractive index of the fourth lens is greater than or equal to 1.72 and less than or equal to 1.76;

[0034] The refractive index of the fifth lens is greater than or equal to 1.74 and less than or equal to 1.78;

[0035] The refractive index of the sixth lens is greater than or equal to 1.71 and less than or equal to 1.75.

[0036] Optionally, the Abbe number of the first lens is greater than or equal to 79.6 and less than or equal to 81.6;

[0037] The Abbe number of the second lens is greater than or equal to 34.5 and less than or equal to 36.5;

[0038] The Abbe number of the third lens is greater than or equal to 26 and less than or equal to 28;

[0039] The Abbe number of the fourth lens is greater than or equal to 44 and less than or equal to 46;

[0040] The Abbe number of the fifth lens is greater than or equal to 27 and less than or equal to 29;

[0041] The Abbe number of the sixth lens is greater than or equal to 54 and less than or equal to 56.

[0042] Optionally, the center thickness of the first lens is greater than or equal to 3.3 and less than or equal to 3.7;

[0043] The center thickness of the second lens is greater than or equal to 4.3 and less than or equal to 4.7;

[0044] The center thickness of the third lens is greater than or equal to 4.8 and less than or equal to 5.2;

[0045] The center thickness of the fourth lens is greater than or equal to 3.8 and less than or equal to 4.2;

[0046] The center thickness of the fifth lens is greater than or equal to 3.3 and less than or equal to 3.7;

[0047] The center thickness of the sixth lens is greater than or equal to 4.8 and less than or equal to 5.2.

[0048] Optionally, the centers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are on the same straight line.

[0049] Optionally, the first lens and the third lens are biconvex lenses;

[0050] The second lens is a negative meniscus lens;

[0051] The fourth lens and the sixth lens are positive meniscus lenses;

[0052] The fifth lens is a biconcave lens.

[0053] Compared with the prior art, the embodiments of the present utility model have the following advantages:

[0054] The first lens group and the second lens group respectively adopt two groups of combined lenses, namely, the first lens and the second lens are closely attached, and the third lens, the fourth lens and the fifth lens are closely attached, which can achieve the effects of achromatism and apochromatism. Moreover, the first lens group, the second lens group and the sixth lens are arranged at intervals in sequence, and the refractive index and dispersion characteristics of different lens groups and lenses are mutually compensated to achieve the effect of achromatism. The problem that the existing microscopic tube lens is difficult to meet the achromatism requirements in the microscopic technology industry is solved. Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the accompanying drawings required for the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] Figure 1 It is a schematic diagram of the overall structure of the achromatic microscopic tube lens in the embodiment of the present application;

[0057] Figure 2 It is a MTF diffraction modulation function diagram of the achromatic microscopic tube lens in the embodiment of the present application;

[0058] Figure 3 It is a field curvature and distortion diagram of the achromatic microscopic tube lens in the embodiment of the present application;

[0059] Figure 4 It is a chromatic focal shift curve diagram of the achromatic microscopic tube lens in the embodiment of the present application.

[0060] Explanation of the Reference Numerals in the Drawings:

[0061] 1. First lens group; 11. First lens; 12. Second lens; 2. Second lens group; 21. Third lens; 22. Fourth lens; 23. Fifth lens; 3. Sixth lens. Detailed Embodiments

[0062] To enable those skilled in the art to better understand the solution of the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0063] The following further elaborates on this application in conjunction with the accompanying drawings of the specification.

[0064] The embodiments of this application disclose an achromatic microscope tube lens.

[0065] As Figure 1 shown, an achromatic microscope tube lens includes a first lens group 1, a second lens group 2, and a sixth lens 3. The first lens group 1 includes a first lens 11 and a second lens 12, and the first lens 11 and the second lens 12 are closely attached; the second lens group 2 includes a third lens 21, a fourth lens 22, and a fifth lens 23, and the third lens 21, the fourth lens 22, and the fifth lens 23 are closely attached in sequence; the first lens group 1, the second lens group 2, and the sixth lens 3 are arranged at intervals in sequence for mutual compensation to eliminate chromatic aberration.

[0066] The achromatic microscope tube lens is placed between the aperture stop and the image plane. The first lens group 1 and the second lens group 2 respectively adopt two groups of combined lenses, that is, the first lens 11 and the second lens 12 are closely attached, and the third lens 21, the fourth lens 22, and the fifth lens 23 are closely attached, which can achieve the effects of achromatism and apochromatism. Moreover, the first lens group 1, the second lens group 2, and the sixth lens 3 are arranged at intervals in sequence, and the refractive index and dispersion characteristics of different lens groups and lenses are mutually compensated to achieve the effect of eliminating chromatic aberration. This solves the problem that the existing microscope tube lens is difficult to meet the achromatic aberration requirements in the microscopic technology industry.

[0067] The achromatic microscope tube lens of this application is, in the direction of optical path transmission (the direction of optical path transmission is the Figure 1 direction from left to right in

[0068] ), the first lens group 1, the second lens group 2, and the sixth lens 3 in sequence.

[0069] Specifically, in the direction of optical path transmission, they are the first lens 11, the second lens 12, the third lens 21, the fourth lens 22, the fifth lens 23, and the sixth lens 3 in sequence.

[0070] The second lens group 2 is also a cemented lens, and the third lens 21, the fourth lens 22, and the fifth lens 23 are sequentially bonded with optical cement or optical glue. The cemented lens can effectively reduce chromatic aberration and improve imaging quality, achieving the effects of achromatism and apochromatism.

[0071] Among them, the first lens 11 and the third lens 21 are biconvex lenses; the second lens 12 is a negative meniscus lens; the fourth lens 22 and the sixth lens 3 are positive meniscus lenses; the fifth lens 23 is a biconcave lens.

[0072] The distance between the first lens 11 and the diaphragm is 21.8 - 22.2 mm; the distance between the second lens 12 and the third lens 21 is 4 - 4.4 mm; the distance between the fifth lens 23 and the sixth lens 3 is 19.6 - 20 mm; the distance between the sixth lens 3 and the image plane is 21.8 - 22.2 mm.

[0073] At the same time, the effective apertures of the first lens 11, the second lens 12, the third lens 21, the fourth lens 22, the fifth lens 23, and the sixth lens 3 are all greater than or equal to 17 mm.

[0074] Regarding the curvature radii of each lens:

[0075] The curvature radius of the surface of the first lens 11 close to the incident light source is greater than or equal to 39 mm and less than or equal to 41 mm (i.e., 39 ≤ R1_near ≤ 41, where R1_near is the curvature radius of the surface of the first lens 11 close to the incident light source, and the unit of R1_near is mm).

[0076] The curvature radius of the surface of the first lens 11 facing away from the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm (i.e., -32 ≤ R1_far ≤ -30, where R1_far is the curvature radius of the surface of the first lens 11 facing away from the incident light source, and the unit of R1_far is mm).

[0077] The curvature radius of the surface of the second lens 12 close to the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm (i.e., -32 ≤ R2_near ≤ -30, where R2_near is the curvature radius of the surface of the second lens 12 close to the incident light source, and the unit of R2_near is mm).

[0078] The radius of curvature of the surface of the second lens 12 facing away from the incident light source is greater than or equal to -208 mm and less than or equal to -206 mm (i.e., -208 ≤ R2 back ≤ -206, where R2 back is the radius of curvature of the surface of the second lens 12 facing away from the incident light source, and the unit of R2 back is mm).

[0079] The radius of curvature of the surface of the third lens 21 facing the incident light source is greater than or equal to 35.6 mm and less than or equal to 37.6 mm (i.e., 35.6 ≤ R3 near ≤ 37.6, where R3 near is the radius of curvature of the surface of the third lens 21 facing the incident light source, and the unit of R3 near is mm).

[0080] The radius of curvature of the surface of the third lens 21 facing away from the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm (i.e., -44.1 ≤ R3 back ≤ -42.1, where R3 back is the radius of curvature of the surface of the third lens 21 facing away from the incident light source, and the unit of R3 back is mm).

[0081] The radius of curvature of the surface of the fourth lens 22 facing the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm (i.e., -44.1 ≤ R4 near ≤ -42.1, where R4 near is the radius of curvature of the surface of the fourth lens 22 facing the incident light source, and the unit of R4 near is mm).

[0082] The radius of curvature of the surface of the fourth lens 22 facing away from the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm (i.e., -22.5 ≤ R4 back ≤ -20.5, where R4 back is the radius of curvature of the surface of the fourth lens 22 facing away from the incident light source, and the unit of R4 back is mm).

[0083] The radius of curvature of the surface of the fifth lens 23 facing the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm (i.e., -22.5 ≤ R5 near ≤ -20.5, where R5 near is the radius of curvature of the surface of the fifth lens 23 facing the incident light source, and the unit of R5 near is mm).

[0084] The radius of curvature of the surface of the fifth lens 23 facing away from the incident light source is greater than or equal to 16.1 mm and less than or equal to 18.1 mm (i.e., 16.1 ≤ R5 back ≤ 18.1, where R5 back is the radius of curvature of the surface of the fifth lens 23 facing away from the incident light source, and the unit of R5 back is mm).

[0085] The radius of curvature of the surface of the sixth lens 3 facing the incident light source is greater than or equal to 28.9 mm and less than or equal to 30.9 mm (i.e., 28.9 ≤ R6 near ≤ 30.9, where R6 near is the radius of curvature of the surface of the sixth lens 3 facing the incident light source, and the unit of R6 near is mm).

[0086] The radius of curvature of the surface of the sixth lens 3 facing away from the incident light source is greater than or equal to 32.2 mm and less than or equal to 34.2 mm (i.e., 32.2 ≤ R6 back ≤ 34.2, where R6 back is the radius of curvature of the surface of the sixth lens 3 facing away from the incident light source, and the unit of R6 back is mm).

[0087] Regarding the refractive index of each lens:

[0088] The refractive index of the first lens 11 is greater than or equal to 1.48 and less than or equal to 1.52;

[0089] The refractive index of the second lens 12 is greater than or equal to 1.78 and less than or equal to 1.82;

[0090] The refractive index of the third lens 21 is greater than or equal to 1.88 and less than or equal to 1.92;

[0091] The refractive index of the fourth lens 22 is greater than or equal to 1.72 and less than or equal to 1.76;

[0092] The refractive index of the fifth lens 23 is greater than or equal to 1.74 and less than or equal to 1.78;

[0093] The refractive index of the sixth lens 3 is greater than or equal to 1.71 and less than or equal to 1.75.

[0094] Regarding the Abbe number of each lens:

[0095] The Abbe number of the first lens 11 is greater than or equal to 79.6 and less than or equal to 81.6;

[0096] The Abbe number of the second lens 12 is greater than or equal to 34.5 and less than or equal to 36.5;

[0097] The Abbe number of the third lens 21 is greater than or equal to 26 and less than or equal to 28;

[0098] The Abbe number of the fourth lens 22 is greater than or equal to 44 and less than or equal to 46;

[0099] The Abbe number of the fifth lens 23 is greater than or equal to 27 and less than or equal to 29;

[0100] The Abbe number of the sixth lens 3 is greater than or equal to 54 and less than or equal to 56.

[0101] Regarding the central thickness of each lens:

[0102] The central thickness of the first lens 11 is greater than or equal to 3.3 and less than or equal to 3.7.

[0103] The central thickness of the second lens 12 is greater than or equal to 4.3 and less than or equal to 4.7.

[0104] The central thickness of the third lens 21 is greater than or equal to 4.8 and less than or equal to 5.2.

[0105] The central thickness of the fourth lens 22 is greater than or equal to 3.8 and less than or equal to 4.2.

[0106] The central thickness of the fifth lens 23 is greater than or equal to 3.3 and less than or equal to 3.7.

[0107] The central thickness of the sixth lens 3 is greater than or equal to 4.8 and less than or equal to 5.2.

[0108] Specifically, the centers of the first lens 11, the second lens 12, the third lens 21, the fourth lens 22, the fifth lens 23, and the sixth lens 3 are on the same straight line.

[0109] In this embodiment, the surface of the lens close to the incident light source is hereinafter referred to as the front surface, and the surface of the lens facing away from the incident light source is hereinafter referred to as the rear surface.

[0110] Along the transmission direction of the incident light source, the refractive index of the first lens 11 is 1.5, the Abbe number is 80.6, and the effective aperture is Φ18 mm.

[0111] The refractive index of the second lens 12 is 1.8, the Abbe number is 35.5, and the effective aperture is Φ18 mm.

[0112] The refractive index of the third lens 21 is 1.9, the Abbe number is 27, and the effective aperture is Φ18 mm.

[0113] The refractive index of the fourth lens 22 is 1.74, the Abbe number is 45, and the effective aperture is Φ18 mm.

[0114] The refractive index of the fifth lens 23 is 1.76, the Abbe number is 28, and the effective aperture is Φ18 mm.

[0115] The refractive index of the sixth lens 3 is 1.73, the Abbe number is 55, and the effective aperture is Φ17 mm.

[0116] Among them, the central distance between the diaphragm and the front surface of the first lens 11 is 22 mm, the central distance between the rear surface of the second lens 12 and the front surface of the third lens 21 is 4.2 mm, the central distance between the rear surface of the fifth lens 23 and the front surface of the sixth lens 3 is 19.8 mm, and the central distance between the rear surface of the sixth lens 3 and the image plane is 22 mm.

[0117] After combining the first lens group 1, the second lens group 2 and the sixth lens 3, the achromatic microtube lens can obtain a lens focal length f of 100 mm and an entrance pupil diameter of 12 mm.

[0118] Since the aperture coefficient = lens focal length / entrance pupil diameter, the aperture F of the achromatic microscope tube can be obtained as F = 100 / 12 ≈ 8.3.

[0119] In the optical design, the design method of diffraction limit is adopted to improve the resolution.

[0120] The formula for the theoretical diffraction limit is sinθ = 1.22λ / D. Where θ is the angular resolution, λ is the wavelength, and D is the aperture diameter. When θ is very small, sinθ is approximately equal to tagθ, approximately equal to d / f, where d is the minimum resolvable size and f is the focal length. It can be considered that d / f = 1.22λ / D, and f / D = d / 1.22λ is deduced. f / D is the focal length / aperture diameter (i.e., the lens focal length / entrance pupil diameter in this application), which is the aperture F value we often mention. When the F value is smaller, the resolution is higher.

[0121] In this application, F = 8.3, reaching the diffraction limit and conforming to the theoretical diffraction limit formula.

[0122] Furthermore, this application satisfies that the absolute value of the ratio of the first lens group 1 to the lens focal length is greater than 3 and less than 4.

[0123] The ratio of the second lens group 2 to the focal length of the lens is greater than -8 and less than -5.

[0124] The absolute value of the ratio of the sixth lens 3 to the focal length of the lens is greater than 2 and less than 3.

[0125] The focal length of the first lens group 1 is f1, the focal length of the second lens group 2 is f2, and the focal length of the sixth lens 3 is f3, that is, 3 < |f1 / f| < 4; -8 < f2 / f < -5; 2 < |f3 / f| < 3.

[0126] When the lens groups of the achromatic microscope tube lens are in the above ratio range with the focal length of the lens, a high resolution effect can be obtained.

[0127] Furthermore, setting the aperture stop at the image-side focal point of the microscope objective can solve the alignment accuracy of the object surface and also reduce the reading accuracy of the image surface, making the illuminance of the entire phase surface uniform and the clarity of the entire picture consistent.

[0128] Such as Figure 2 、 Figure 3 and Figure 4 As shown, actual numerical tests are carried out on the achromatic microscope tube lens, and its optical design indicators include: modulation transfer function (MTF) diffraction modulation function diagram, field curvature and distortion diagram, and chromatic focal shift curve diagram.

[0129] Among them, as Figure 2 shown, it can be seen from the MTF diffraction modulation function diagram that the imaging resolutions of different colors are very close to the diffraction limit and have met the requirements of high-definition resolution.

[0130] Such as Figure 3 shown, the left side is the field curvature diagram and the right side is the distortion diagram. It can be seen from the field curvature diagram that the field curvature changes of the meridian line and the sagittal line within the entire field of view are both within 0.01, which belongs to a small field curvature optical system in the machine vision system.

[0131] Similarly, it can be seen from the distortion diagram that the distortion of the entire system in each field of view is less than 0.5%, which can be regarded as a non-distortion system. In this way, there is no impact or change on the imaging of the object, and its application range or precision measurement, etc. can be expanded.

[0132] Such as Figure 4 shown, it can be seen from the chromatic focal shift curve diagram that the abscissa is the focal shift, and the focal shift represents the distance of the focus movement of different color lights after passing through this achromatic microscope tube lens (i.e., chromatic aberration). The smaller the focal shift distance value, the better the consistency of the image within the working wavelength range. It can be seen from the figure that the maximum focal shift range is 29 microns.

[0133] It can be seen from the structure of the above achromatic microscope tube lens and the actual data detection that the structure of the present application has the following effects:

[0134] 1. A complex optical design with three groups of six lenses in total is adopted. By precisely configuring the radius of curvature, thickness, refractive index, and Abbe number, an achromatic microscope tube lens with high resolution, low distortion, and low chromatic aberration is achieved.

[0135] 2. Advanced achromatic and apochromatic effects are achieved through two groups of cemented lenses, significantly improving the imaging quality.

[0136] 3. Ensure that the optical system reaches the diffraction limit to meet the requirements of high-precision imaging.

[0137] 4. Through refractive index matching technology, the optical performance is further optimized to improve the overall imaging quality of the system.

[0138] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0139] It should be noted that the present utility model takes an achromatic microscope tube lens as an example to introduce the specific structure and working principle of the present utility model. However, the application of the present utility model is not limited to an achromatic microscope tube lens, and it can also be applied to the production and use of other similar workpieces.

[0140] It should be understood that the present utility model is not limited to the precise structure already described and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present utility model is only limited by the appended claims.

[0141] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An achromatic microtuboscope, characterized in that Comprising: A first lens group, including a first lens and a second lens, the first lens and the second lens being closely attached; A second lens group, including a third lens, a fourth lens, and a fifth lens, the third lens, the fourth lens, and the fifth lens being closely attached in sequence; A sixth lens; The first lens group, the second lens group, and the sixth lens are arranged at intervals in sequence for mutual compensation to eliminate chromatic aberration.

2. The achromatic microendoscope according to claim 1, characterized in that, The distance between the first lens and the diaphragm is 21.8 - 22.2 mm; The distance between the second lens and the third lens is 4 - 4.4 mm; The distance between the fifth lens and the sixth lens is 19.6 - 20 mm; The distance between the sixth lens and the image plane is 21.8 - 22.2 mm.

3. The achromatic microendoscope according to claim 2, characterized in that, The effective apertures of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all greater than or equal to 17 mm.

4. The achromatic microscope tube lens according to claim 3, characterized in that, The absolute value of the ratio of the first lens group to the lens focal length is greater than 3 and less than 4; The ratio of the second lens group to the lens focal length is greater than -8 and less than -5; The absolute value of the ratio of the sixth lens to the lens focal length is greater than 2 and less than 3.

5. The apochromatic microtelescope according to claim 4, wherein The radius of curvature of the surface of the first lens facing the incident light source is greater than or equal to 39 mm and less than or equal to 41 mm; The radius of curvature of the surface of the first lens facing away from the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm; The radius of curvature of the surface of the second lens facing the incident light source is greater than or equal to -32 mm and less than or equal to -30 mm; The radius of curvature of the surface of the second lens facing away from the incident light source is greater than or equal to -208 mm and less than or equal to -206 mm; The radius of curvature of the surface of the third lens facing the incident light source is greater than or equal to 35.6 mm and less than or equal to 37.6 mm; The radius of curvature of the surface of the third lens facing away from the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm; The radius of curvature of the surface of the fourth lens facing the incident light source is greater than or equal to -44.1 mm and less than or equal to -42.1 mm; The radius of curvature of the surface of the fourth lens facing away from the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm; The radius of curvature of the surface of the fifth lens close to the incident light source is greater than or equal to -22.5 mm and less than or equal to -20.5 mm; The radius of curvature of the surface of the fifth lens facing away from the incident light source is greater than or equal to 16.1 mm and less than or equal to 18.1 mm; The radius of curvature of the surface of the sixth lens close to the incident light source is greater than or equal to 28.9 mm and less than or equal to 30.9 mm; The radius of curvature of the surface of the sixth lens facing away from the incident light source is greater than or equal to 32.2 mm and less than or equal to 34.2 mm.

6. The achromatic microscope tube lens according to claim 5, wherein, The refractive index of the first lens is greater than or equal to 1.48 and less than or equal to 1.52; The refractive index of the second lens is greater than or equal to 1.78 and less than or equal to 1.82; The refractive index of the third lens is greater than or equal to 1.88 and less than or equal to 1.92; The refractive index of the fourth lens is greater than or equal to 1.72 and less than or equal to 1.76; The refractive index of the fifth lens is greater than or equal to 1.74 and less than or equal to 1.78; The refractive index of the sixth lens is greater than or equal to 1.71 and less than or equal to 1.

75.

7. The achromatic microscope tube lens according to claim 6, wherein, The Abbe number of the first lens is greater than or equal to 79.6 and less than or equal to 81.6; The Abbe number of the second lens is greater than or equal to 34.5 and less than or equal to 36.5; The Abbe number of the third lens is greater than or equal to 26 and less than or equal to 28; The Abbe number of the fourth lens is greater than or equal to 44 and less than or equal to 46; The Abbe number of the fifth lens is greater than or equal to 27 and less than or equal to 29; The Abbe number of the sixth lens is greater than or equal to 54 and less than or equal to 56.

8. The apochromatic microscope tube lens according to claim 7, wherein, The center thickness of the first lens is greater than or equal to 3.3 and less than or equal to 3.7; The center thickness of the second lens is greater than or equal to 4.3 and less than or equal to 4.7; The center thickness of the third lens is greater than or equal to 4.8 and less than or equal to 5.2; The center thickness of the fourth lens is greater than or equal to 3.8 and less than or equal to 4.2; The center thickness of the fifth lens is greater than or equal to 3.3 and less than or equal to 3.7; The center thickness of the sixth lens is greater than or equal to 4.8 and less than or equal to 5.

2.

9. The achromatic microscope tube lens according to claim 1, characterized in that, The centers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are on the same straight line.

10. The achromatic microscope tube lens according to claim 1, characterized in that, The first lens and the third lens are biconvex lenses; The second lens is a negative meniscus lens; The fourth lens and the sixth lens are positive meniscus lenses; The fifth lens is a biconcave lens.

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