Long working distance wide spectrum microscope objective

Abstract

The long working distance wide spectrum microscope objective lens belongs to the technical field of microscope objective lenses, and its purpose is to solve the problems of short working spectrum and short working distance in the prior art. The long working distance wide spectrum microscope objective lens of the present invention includes a first lens group, a second lens group and a third lens group arranged in sequence along the optical axis direction; the first lens group includes a first lens, the second lens group includes a second lens, a third lens and a fourth lens, and the optical focal length distribution of the first lens group, the second lens group and the third lens group is positive, negative and negative respectively; the optical focal length distribution of the second lens, the third lens and the fourth lens of the second lens group is negative, positive and negative respectively; the present invention realizes 0.4-0.8μm wide spectrum imaging through the distribution of four materials and the limitation of five lens structures; the distance from the second surface of the fifth lens to the object plane OS1 is the working distance, and the working distance of the present invention is greater than or equal to 0.38f. Long working distance wide spectrum imaging is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of microscope objective lenses, and in particular relates to a microscope objective lens with a long working distance and a wide spectrum. Background Art

[0002] The objective lens is a lens group composed of several lenses. The purpose of using a combination is to overcome the imaging defects of a single lens and improve the optical quality of the objective lens. The magnification effect of a microscope mainly depends on the objective lens. The working distance of a microscope objective lens refers to the distance from the bottom of the front lens of the objective lens to the top of the specimen's coverslip when the observed specimen is clearest. The working distance of the objective lens is related to the focal length of the objective lens. The longer the focal length of the objective lens, the lower the magnification and the longer its working distance. As the spectral response range of the detector increases, the imaging spectral range of the microscope objective lens is also required to increase. In order to adapt to different working environments, the working range of the microscope objective lens is also required to increase. The microscope objective lens in the existing technology has a short working spectrum and a small working distance. Summary of the Invention

[0003] The purpose of the present invention is to provide a microscope objective lens with a long working distance and a wide spectrum, so as to solve the problems of the microscope objective lens in the prior art, such as a short working spectrum and a small working distance.

[0004] To achieve the above-mentioned object, the long working distance wide spectrum microscope objective lens of the present invention comprises a first lens group, a second lens group, and a third lens group arranged in sequence along the optical axis; the first lens group comprises a first lens element, the second lens group comprises a second lens element, a third lens element, and a fourth lens element, and the third lens group comprises a fifth lens element; the optical power distribution of the first lens group, the second lens group, and the third lens group is positive, negative, and negative, respectively; the optical power distribution of the second lens element, the third lens element, and the fourth lens element of the second lens group is negative, positive, and negative, respectively;

[0005] The ratio of the focal length f of the first lens group, the second lens group, and the third lens group to the entire optical system meets the following requirements:

[0006] 0.1 <fg1 / f<0.5;

[0007] -0.7 <fg2 / f<-0.3;

[0008] -0.7 <fg3 / f<-0.3;

[0009] Where: f is the focal length of the entire optical system

[0010] fg1 is the focal length of the first lens group;

[0011] fg2 is the focal length of the second lens group;

[0012] fg3 is the focal length of the third lens group;

[0013] The ratio of the focal length fg2 of the second lens, the third lens, and the fourth lens to the second lens group meets the following requirements:

[0014] -0.7 <fl2 / fg2<-0.3;

[0015] -0.7 <fl3 / fg2<-0.3;

[0016] -0.7 <fl4 / fg2<-0.3;

[0017] in:

[0018] fl2 is the focal length of the second lens;

[0019] fl3 is the focal length of the third lens;

[0020] fl4 is the focal length of the fourth lens;

[0021] The optical system aperture is 0 to 15 mm in front of the first lens group.

[0022] The microscope objective lens achieves 0.4-0.8 μm wide spectrum imaging by combining four materials. Any four of the five lenses of the limiting objective lens are selected from the four materials in a one-to-one correspondence, and the remaining lens is selected from any one of the four materials; the refractive index and dispersion coefficient of the four materials are:

[0023] Refractive index Dispersion coefficient Material name Material 1 1.497 81.613 H-FK61 Material 2 1.744 49.59 D-LAF50 Material 3 1.525 70.361 D-PK3 Material 4 1.9229 20.88 H-ZF62 .

[0024] The optical parameters of the microscope objective are:

[0025]

[0026]

[0027] The present invention has the following beneficial effects: the long working distance, wide spectrum microscope objective lens comprises three lens groups, each composed of five lens elements, each of which is made of four materials. By distributing these four materials and limiting the structure of the five lens elements, wide spectrum imaging of 0.4-0.8 μm is achieved. The distance from the second surface of the fifth lens element to the object plane OS1 is the working distance, and the working distance of the present invention is greater than or equal to 0.38f. This achieves long working distance, wide spectrum imaging, a compact positive lens structure, good imaging quality, and a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the long working distance and wide spectrum microscope objective lens of the present invention;

[0029] Figure 2 This is a structural diagram of the optical system of the long working distance and wide spectrum microscope objective lens of the present invention;

[0030] Figure 3 This is a diagram of the optical imaging quality of the long working distance and wide spectrum microscope objective lens of the present invention;

[0031] Among them: G1, the first lens group, G2, the second lens group, G3, the third lens group, L1, the first lens, L2, the second lens, L3, the third lens, L4, the fourth lens, L5, the fifth lens. DETAILED DESCRIPTION

[0032] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0033] See attached Figure 1 and attached Figure 2 The long working distance and wide spectrum microscope objective lens of the present invention includes a first lens group G1, a second lens group G2, and a third lens group G3 arranged in sequence along the optical axis; the first lens group G1 includes a first lens L1, the second lens group G2 includes a second lens L2, a third lens L3, and a fourth lens L4, and the third lens group G3 includes a fifth lens L5; the focal powers of the first lens group G1, the second lens group G2, and the third lens group G3 are respectively positive, negative, and negative; the focal powers of the second lens L2, the third lens L3, and the fourth lens L4 of the second lens group G2 are respectively negative, positive, and negative;

[0034] The ratio of the focal length f of the first lens group G1, the second lens group G2, and the third lens group G3 to the entire optical system meets the following requirements:

[0035] 0.1 <fg1 / f<0.5;

[0036] -0.7 <fg2 / f<-0.3;

[0037] -0.7 <fg2 / f<-0.3;

[0038] Where: f is the focal length of the entire optical system

[0039] fg1 is the focal length of the first lens group G1;

[0040] fg2 is the focal length of the second lens group G2;

[0041] fg3 is the focal length of the third lens group G3;

[0042] The ratio of the focal length fg2 of the second lens L2, the third lens L3, the fourth lens L4 and the second lens group G2 meets the following requirements:

[0043] -0.7 <fl2 / fg2<-0.3;

[0044] -0.7 <fl3 / fg2<-0.3;

[0045] -0.7 <fl4 / fg2<-0.3;

[0046] in:

[0047] fl2 is the focal length of the second lens L2;

[0048] fl3 is the focal length of the third lens L3;

[0049] fl4 is the focal length of the fourth lens L4;

[0050] The optical system aperture is located 0 to 15 mm in front of the first lens group G1.

[0051] The microscope objective lens achieves 0.4-0.8 μm wide spectrum imaging by combining four materials. Any four of the five lenses of the limiting objective lens are selected from the four materials in a one-to-one correspondence, and the remaining lens is selected from any one of the four materials; the refractive index and dispersion coefficient of the four materials are:

[0052] Refractive index Dispersion coefficient Material name Material 1 1.497 81.613 H-FK61 Material 2 1.744 49.59 D-LAF50 Material 3 1.525 70.361 D-PK3 Material 4 1.9229 20.88 H-ZF62 .

[0053] The optical parameters of the microscope objective are:

[0054]

[0055] The distance between the second surface S10 of the fifth lens L5 and the object plane OS1 is the working distance, and the working distance is ≥0.38f.

[0056] See attached Figure 3 , the transfer function of the optical system has reached the reflection limit, has good optical imaging quality, and meets the applicable requirements.

Claims

1. Long working distance and wide spectrum microscope objective lens, characterized by: The invention comprises a first lens group (G1), a second lens group (G2) and a third lens group (G3) which are sequentially arranged along an optical axis; the first lens group (G1) comprises a first lens (L1), the second lens group (G2) comprises a second lens (L2), a third lens (L3) and a fourth lens (L4), and the third lens group (G3) comprises a fifth lens (L5); the optical power distribution of the first lens group (G1), the second lens group (G2) and the third lens group (G3) is positive, negative and negative respectively; the optical power distribution of the second lens (L2), the third lens (L3) and the fourth lens (L4) of the second lens group (G2) is negative, positive and negative respectively; The ratio of the focal length f of the first lens group (G1), the second lens group (G2), and the third lens group (G3) to the entire optical system meets the following requirements: 0.1 <fg1 / f<0.5; -0.7 <fg2 / f<-0.3; -0.7 <fg3 / f<-0.3; Where: f is the focal length of the entire optical system fg1 is the focal length of the first lens group (G1); fg2 is the focal length of the second lens group (G2); fg3 is the focal length of the third lens group (G3); The ratio of the focal length fg2 of the second lens (L2), the third lens (L3), and the fourth lens (L4) to the second lens group (G2) meets the following requirements: -0.7 <fl2 / fg2<-0.3; -0.7 <fl3 / fg2<-0.3; -0.7 <fl4 / fg2<-0.3; in: fl2 is the focal length of the second lens (L2); fl3 is the focal length of the third lens (L3); fl4 is the focal length of the fourth lens (L4); The optical system aperture is located 0 to 15 mm in front of the first lens group (G1).

2. The long working distance wide spectrum microscope objective lens according to claim 1, characterized in that: The microscope objective lens achieves 0.4-0.8 μm wide spectrum imaging by combining four materials. Any four of the five lenses of the microscope objective lens are selected from the four materials in a one-to-one correspondence, and the remaining lens is selected from any one of the four materials. The refractive index and dispersion coefficient of the four materials are: 。 3. The long working distance wide spectrum microscope objective lens according to claim 1 or 2, characterized in that: The optical parameters of the microscope objective are:

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