A plan-field apochromatic microscope objective lens for materials analysis equipment

Abstract

This invention relates to a plan-field apochromatic microscope objective lens for materials analysis equipment, comprising: a first lens with positive optical power and biconvexity arranged sequentially along the optical axis from the object side; a second lens with negative optical power and biconcaveness; a first cemented doublet lens group with positive optical power composed of a third and a fourth lens; a second cemented doublet lens group with positive optical power composed of a fifth and a sixth lens; a third cemented doublet lens group with positive optical power composed of a seventh and an eighth lens; a ninth lens with positive optical power and its concave surface facing the image plane; and a tenth lens with positive optical power and its concave surface facing the image plane. The plan-field apochromatic microscope objective lens for materials analysis equipment provided by this invention possesses both plan-field and apochromatic characteristics, enabling clear and stable imaging.

Description

Technical Field

[0001] This invention relates to an optical lens system, and more specifically, to a plan apochromatic microscope objective lens for a materials analysis apparatus. Background Technology

[0002] With the rapid development of materials science, semiconductor industry, life sciences, and nanotechnology, the demand for high-precision, high-fidelity observation and analysis of the microstructure of materials is becoming increasingly urgent. As the core optical component of various materials analysis equipment, the imaging quality of the microscope objective directly determines the resolution, contrast, color reproduction accuracy, and quantitative analysis accuracy of the equipment.

[0003] Currently, high-end equipment often uses plan achromatic or plan semi-apochromatic objectives. The former has insufficient chromatic aberration correction, while the latter still has limitations in complex multi-wavelength analyses. High-performance apochromatic objectives either sacrifice plan performance in pursuit of ultimate correction, or their complex structure, high cost, and poor environmental adaptability are due to the use of a large number of special materials. They are difficult to balance a large field of view, long working distance, and high numerical aperture in a compact size, which limits their widespread application in industrial-grade analytical equipment.

[0004] Therefore, there is a need in this field for a new type of plan-field apochromatic microscope objective that can achieve excellent wide-spectrum apochromaticity and strict plan-field correction while also taking into account high numerical aperture, long working distance, compact structure and good manufacturability and economy. This would provide a reliable optical core for the next generation of high-precision materials analysis equipment and meet the growing demand of cutting-edge scientific research and high-end industrial testing for high-quality, high-efficiency and high-reliability microscopic imaging and analysis. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a plan apochromatic microscope objective lens for materials analysis equipment. This invention consists of ten spherical lenses, which can simultaneously achieve excellent apochromatic correction and strict plan correction, and has a compact structure and excellent performance.

[0006] This invention specifically relates to a plan-field apochromatic microscope objective lens for a materials analysis equipment, comprising: a first lens having positive optical power and being biconvex, arranged sequentially along the optical axis from the object side; a second lens having negative optical power and being biconcave; a first cemented doublet lens group having positive optical power composed of a third lens and a fourth lens; a second cemented doublet lens group having positive optical power composed of a fifth lens and a sixth lens; a third cemented doublet lens group having positive optical power composed of a seventh lens and an eighth lens; a ninth lens having positive optical power with its concave surface facing the image plane; and a tenth lens having positive optical power with its concave surface facing the image plane.

[0007] The optical power of the first lens is Φ1, the optical power of the second lens is Φ2, and the optical power of the first cemented doublet lens group is Φ. 34 The optical power of the second cemented doublet lens group is Φ 56 And the optical power of the third cemented doublet lens group is Φ 78 The optical power of the ninth lens is Φ9, and the optical power of the tenth lens is Φ. 10 The optical power of the entire lens assembly is Φ, which satisfies the following relationship: 0.15≤Φ≤0.36;

[0008] The total optical length of the lens assembly, i.e., TTL < 35mm, and the optical power Φ1 of the first lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.4 ≤ Φ1 / Φ ≤ 0.52. The optical powers of the first cemented doublet lens group, the second cemented doublet lens group, and the third cemented doublet lens group satisfy the following relationship: Φ34 > Φ78 > Φ56 > 0, 30 < Φ34 / Φ56 < 55, 1 < Φ34 / Φ78 < 5, 0.01 < Φ56 / Φ78 < 0.05. The sum of the three lenses accounts for the proportion of the optical power of the entire system within the range of: 0.20 ≤ (Φ34 + Φ56 + Φ78) / φ ≤ 0.3.

[0009] Furthermore, the optical power Φ2 of the second lens and the optical power Φ of the entire lens assembly satisfy the following relationship: -0.97≤Φ2 / Φ≤-0.21.

[0010] Furthermore, the optical power Φ of the first cemented doublet lens group 34 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.168 ≤ Φ 34 / Φ≤0.24.

[0011] Furthermore, the optical power Φ of the second cemented doublet lens group 56 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.0033 ≤ Φ 56 / Φ≤0.0054.

[0012] Furthermore, the optical power Φ of the third cemented doublet lens group 78 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.025 ≤ Φ 78 / Φ≤0.036.

[0013] Furthermore, the optical power Φ9 of the ninth lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.022≤Φ9 / Φ≤0.028.

[0014] Furthermore, the optical power Φ of the tenth lens 10 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.015 ≤ Φ10 / Φ≤0.03.

[0015] Furthermore, the Abbe number of the third lens in the first cemented doublet lens group is Vd3 and the Abbe number of the fourth lens is Vd4, satisfying the following relationship: 20 < |Vd4 - Vd3| < 35.

[0016] Furthermore, the Abbe number of the fifth lens in the second cemented doublet lens group is Vd5, and the Abbe number of the sixth lens is Vd6, satisfying the following relationship: 30 < |Vd5 - Vd6| < 50.

[0017] Furthermore, the Abbe number of the seventh lens in the third cemented doublet lens group is Vd7 and the Abbe number of the eighth lens is Vd8, satisfying the following relationship: 30 < |Vd7 - Vd8| < 55.

[0018] Furthermore, this invention proposes a plan-field apochromatic microscope objective lens for materials analysis equipment that can simultaneously achieve excellent apochromaticity and strict plan correction, and has a compact structure and excellent performance. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of the plan-field apochromatic microscope objective lens used in the material analysis equipment of the present invention;

[0021] Figure 2 This is a schematic diagram of the axial chromatic aberration of the plan-field apochromatic microscope objective lens used in the material analysis equipment of the present invention;

[0022] Figure 3 This is a schematic diagram of the modulation transfer function of the planar apochromatic microscope objective lens used in the material analysis equipment of this invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0024] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0025] In the following description, the shape (convex or concave) of the lens element surface is defined as viewed from the corresponding side (i.e., from the object side or from the image side).

[0026] In the embodiments disclosed in this invention, the plan-field apochromatic microscope objective lens for a material analysis device, arranged sequentially from the object side to the image side, includes: a first lens A1 with positive optical power and biconvexity, arranged along the optical axis from the object side; a second lens A2 with negative optical power and biconcaveness; and a first cemented doublet group A with positive optical power, composed of a third lens A3 and a fourth lens A4. 34 The second cemented doublet group A, consisting of the fifth lens A5 and the sixth lens A6, has positive optical power. 56 The third cemented doublet group A, consisting of the seventh lens A7 and the eighth lens A8, has positive optical power. 78 A9 is a ninth lens with positive optical power and concave surface facing the image plane, and A10 is a tenth lens with positive optical power and concave surface facing the image plane.

[0027] In one embodiment, such as Figure 1 As shown, in the embodiment of the present invention, the first lens A1 is a biconvex lens element with positive optical power; the second lens A2 is a biconcave lens element with negative optical power.

[0028] In a preferred embodiment, the third lens A3 is a lens element having a concave object-side surface S31 and a concave image-side surface S32 and having negative optical power, and the fourth lens A4 is a lens element having a convex object-side surface S41 and a convex image-side surface S42 and having positive optical power. The third lens A3 and the fourth lens A4 constitute a first cemented doublet lens group A with positive optical power. 34 .

[0029] In a preferred embodiment, the fifth lens A5 is a lens element having a convex object-side surface S51 and a convex image-side surface S52 and having positive optical power, and the sixth lens A6 is a lens element having a concave object-side surface S61 and a convex image-side surface S62 and having negative optical power. The fifth lens A5 and the sixth lens A6 together form a second cemented doublet lens group A with positive optical power. 56 .

[0030] In a preferred embodiment, the seventh lens A7 is a lens element having a convex object-side surface S71 and a convex image-side surface S72 and having positive optical power, and the eighth lens A8 is a lens element having a concave object-side surface S81 and a convex image-side surface S82 and having negative optical power. The seventh lens A7 and the eighth lens A8 together form a third cemented doublet lens group A with positive optical power. 78 .

[0031] In a preferred embodiment, the ninth lens A9 is a lens element having a convex object-side surface S91 and a concave image-side surface S92 and having positive optical power. The tenth lens A10 is a lens element having a convex object-side surface S101 and a concave image-side surface S102 and having positive optical power.

[0032] It should be noted that the three cemented doublet lens groups in this invention are all made of two spherical lenses cemented together, and all have positive optical power. The refractive index and Abbe number of the materials of these three cemented doublet lens groups are configured in a coordinated manner to achieve smoothing of the optical path and reasonable distribution of optical power, while effectively realizing apochromatic correction and flat field correction, thereby helping to eliminate chromatic aberration in the entire optical system.

[0033] In this plan-field apochromatic microscope objective, three sets of cemented doublets together constitute the core correction unit of the system. They utilize glass combinations with large Abbe number differences and optical power distribution to synergistically achieve apochromatic correction over a wide spectral range, effectively eliminating axial and magnification chromatic aberration. At the same time, these three sets of positive optical power cemented doublets rationally distribute the system's optical power, significantly correcting field curvature and achieving strictly plan-field imaging.

[0034] In addition, the image sensor P is positioned at the image plane for imaging.

[0035] In the specific embodiments disclosed in this invention, the optical power of the first lens is Φ1, the optical power of the second lens is Φ2, the optical power of the first cemented doublet lens group is Φ34, the optical power of the second cemented doublet lens group is Φ56, and the optical power of the third cemented doublet lens group is Φ 78 The optical power of the ninth lens is Φ9, and the optical power of the tenth lens is Φ. 10 The optical power of the entire lens assembly is Φ, which satisfies the following relationship: 0.15≤Φ≤0.36;

[0036] In one embodiment, the optical power of the first cemented doublet lens group, the second cemented doublet lens group, and the third cemented doublet lens group satisfies the following relationship: Φ34>Φ78>Φ56>0, 30<Φ34 / Φ56<55, 1<Φ34 / Φ78<5, 0.01<Φ56 / Φ78<0.05, and the sum of the three accounts for the proportion of the total optical power of the system in the range of: 0.20≤(Φ34+Φ56+Φ78) / φ≤0.3;

[0037] Wherein, the total optical length of the lens assembly, i.e., TTL < 35mm, and the optical power Φ1 of the first lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.4 ≤ Φ1 / Φ ≤ 0.52.

[0038] In one embodiment, the optical power Φ2 of the second lens and the optical power Φ of the entire lens assembly satisfy the following relationship: -0.97≤Φ2 / Φ≤-0.21.

[0039] In one embodiment, the optical power Φ of the first cemented doublet lens group 34 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.168 ≤ Φ 34 / Φ≤0.24.

[0040] In one embodiment, the optical power Φ of the second cemented doublet lens group 56 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.0033 ≤ Φ 56 / Φ≤0.0054.

[0041] In one embodiment, the optical power Φ of the third cemented doublet lens group 78 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.025 ≤ Φ 78 / Φ≤0.036.

[0042] In one embodiment, the optical power Φ9 of the ninth lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.022≤Φ9 / Φ≤0.028.

[0043] In one embodiment, the optical power Φ of the tenth lens 10 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.015 ≤ Φ 10 / Φ≤0.03.

[0044] In one embodiment, the Abbe number of the third lens in the first cemented doublet lens group is Vd3 and the Abbe number of the fourth lens is Vd4, satisfying the following relationship: 20 < |Vd4 - V3| < 35.

[0045] In one embodiment, the refractive index of the third lens in the first cemented doublet lens group is n3, and the refractive index of the fourth lens is n4, satisfying the following relationship: 0 < |n3-n4| < 0.28.

[0046] In one embodiment, the Abbe number of the fifth lens in the second cemented doublet lens group is Vd5 and the Abbe number of the sixth lens is Vd6, satisfying the following relationship: 30 < |Vd5 - Vd6| < 50.

[0047] In one embodiment, the refractive index of the fifth lens in the second cemented doublet lens group is n5, and the refractive index of the sixth lens is n6, satisfying the following relationship: -0.194 < |n5-n6| < 0.

[0048] In one embodiment, the Abbe number of the seventh lens in the third cemented doublet lens group is Vd7 and the Abbe number of the eighth lens is Vd8, satisfying the following relationship: 30 < |Vd7 - Vd8| < 55.

[0049] In one embodiment, the refractive index of the seventh lens in the third cemented doublet lens group is n7, and the refractive index of the eighth lens is n8, satisfying the following relationship: -0.27 < |n7-n8| < 0.

[0050] In this invention, all lens element surfaces are spherical. Detailed optical data for each lens element in specific embodiments are given in Table 1, where the radius of curvature (R), lens element thickness, and / or distance between elements along the optical axis, as well as the diameter, are expressed in mm. "Nd" is the refractive index, and "Vd" is the Abbe number.

[0051] In Table 1, the distances between the various elements (and / or surfaces) are labeled "Ln" and measured along the optical axis z. Each number is measured from the previous surface.

[0052] As shown in Table 1, in a preferred embodiment, the first distance L1 from surface S11 to surface S12 is 1 mm, that is, the thickness of the first lens A1 is 1 mm; the air gap L2 between surfaces S12 and S21 is 0.2 mm, that is, the distance between the first lens A1 and the second lens A2 is 0.2 mm; the distance L3 between surfaces S21 and S22 is 1 mm, that is, the thickness of the second lens A2 is 1 mm, and so on.

[0053] Table 1

[0054]

[0055] Figure 2 This diagram illustrates the axial chromatic aberration of the plan-field apochromatic microscope objective lens for materials analysis equipment according to the present invention. Axial chromatic aberration represents the difference in focusing position of light of different wavelengths along the optical axis and is an important indicator of chromatic aberration analysis. The horizontal axis (X-axis) represents the wavelength, ranging from short-wavelength (blue light) to long-wavelength (red light); the vertical axis (Y-axis) represents the offset of the focusing position relative to the reference wavelength, with positive and negative values ​​indicating the difference in the position of the focal point in front of the image. Multiple curves correspond to the focusing positions of light of different wavelengths, ideally coinciding with the zero line; greater separation indicates more severe chromatic aberration. The diagram demonstrates that the plan-field apochromatic microscope objective lens for materials analysis equipment proposed in this invention possesses excellent achromatic characteristics.

[0056] Figure 3 The figure shows a schematic diagram of the modulation transfer function (MTF) curve of a plan-field apochromatic microscope objective lens used in materials analysis equipment. The uppermost black solid line, which is close to a straight line, represents the diffraction limit, which is the theoretical maximum resolving power of the lens assembly. The other curves are schematic diagrams of the MTF curves of the variable magnification endoscope lens of the present invention at multiple field angles. It can be seen that these MTF curves are all close to the diffraction limit. The closer they are to the diffraction limit, the higher the lens resolving power. It can be seen from the figure that the plan-field apochromatic microscope objective lens for materials analysis equipment proposed in this invention has excellent resolving power.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A plan-field apochromatic microscope objective lens for materials analysis equipment, characterized in that, include: Arranged sequentially along the optical axis from the object side are: a first lens with positive optical power and biconvexity; a second lens with negative optical power and biconcaveness; a first cemented doublet group with positive optical power consisting of a third lens and a fourth lens; a second cemented doublet group with positive optical power consisting of a fifth lens and a sixth lens; a third cemented doublet group with positive optical power consisting of a seventh lens and an eighth lens; a ninth lens with positive optical power and concave surface facing the image plane; and a tenth lens with positive optical power and concave surface facing the image plane. The optical power of the first lens is Φ1, the optical power of the second lens is Φ2, and the optical power of the first cemented doublet lens group is Φ. 34 The optical power of the second cemented doublet lens group is Φ 56 And the optical power of the third cemented doublet lens group is Φ 78 The optical power of the ninth lens is Φ9, and the optical power of the tenth lens is Φ. 10 The optical power of the entire lens assembly is Φ, which satisfies the following relationship: 0.15≤Φ≤0.36; The total optical length of the lens assembly, i.e., TTL < 35mm, and the optical power Φ1 of the first lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.4 ≤ Φ1 / Φ ≤ 0.

52. The optical powers of the first cemented doublet lens group, the second cemented doublet lens group, and the third cemented doublet lens group satisfy the following relationship: Φ34 > Φ78 > Φ56 > 0, 30 < Φ34 / Φ56 < 55, 1 < Φ34 / Φ78 < 5, 0.01 < Φ56 / Φ78 < 0.

05. The sum of the three lenses accounts for the proportion of the optical power of the entire system within the range of: 0.20 ≤ (Φ34 + Φ56 + Φ78) / φ ≤ 0.

3.

2. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ2 of the second lens and the optical power Φ of the entire lens assembly satisfy the following relationship: -0.97≤Φ2 / Φ≤-0.

21.

3. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ of the first cemented doublet lens group 34 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.168 ≤ Φ 34 / Φ≤0.

24.

4. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ of the second cemented doublet lens group 56 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.0033 ≤ Φ 56 / Φ≤0.0054.

5. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ of the third cemented doublet lens group 78 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.025 ≤ Φ 78 / Φ≤0.

036.

6. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ9 of the ninth lens and the optical power Φ of the entire lens assembly satisfy the following relationship: 0.022≤Φ9 / Φ≤0.

028.

7. The plan-field apochromatic microscope objective lens for materials analysis equipment according to claim 1, characterized in that, The optical power Φ of the tenth lens 10 The optical power Φ of the entire lens assembly satisfies the following relationship: 0.015 ≤ Φ 10 / Φ≤0.

03.

8. The plan-field apochromatic microscope objective lens for a materials analysis apparatus according to any one of claims 1-7, characterized in that, The Abbe number of the third lens in the first cemented doublet lens group is Vd3 and the Abbe number of the fourth lens is Vd4, satisfying the following relationship: 20 < |Vd4 - Vd3| < 35.

9. The plan-field apochromatic microscope objective lens for a materials analysis apparatus according to any one of claims 1-7, characterized in that, The Abbe number of the fifth lens in the second cemented doublet lens group is Vd5, and the Abbe number of the sixth lens is Vd6, satisfying the following relationship: 30 < |Vd5 - Vd6| < 50.

10. The plan-field apochromatic microscope objective lens for a materials analysis apparatus according to any one of claims 1-7, characterized in that, The Abbe number of the seventh lens in the third cemented doublet lens group is Vd7, and the Abbe number of the eighth lens is Vd8, satisfying the following relationship: 30 < |Vd7 - Vd8| < 55.

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