Microscope objective and imaging device

Abstract

The application provides a microscope objective and an imaging device, and relates to the technical field of optical lenses, wherein the microscope objective comprises, from an object side to an image side, a first lens group G1, a second lens group G2 and a third lens group G3; the first lens group and the third lens group have negative focal powers, and the second lens group has a positive focal power; the second lens group comprises a set of three cemented lenses; the technical scheme provided by the application realizes a long working distance, a large NA and a high resolution of the microscope objective compared with the same magnification microscope objective by reasonable focal power matching among the first lens group, the second lens group and the third lens group; the three cemented lenses are made of glass materials with specific refractive indexes and Abbe numbers, and thus the microscope objective can realize visible light and near-infrared confocal focusing; and the microscope objective can better meet the increasingly diversified and complex requirements of the market.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to a microscope objective and imaging device. Background Technology

[0002] With the increasing national demand and investment in fields such as semiconductors, life sciences, and microscopic detection, many new requirements have been placed on the performance of microscope objectives widely used in these fields. For example, to prevent microscope objectives from contacting and damaging the test samples and to provide a safe operating space, microscope objectives are required to have a longer working distance; to capture weak biological fluorescence and increase the amount of light entering the microscope, microscope objectives are required to have a larger numerical aperture; and to enable comprehensive observation of the test samples using multiple wavelengths, microscope objectives are required to be confocal in the visible and near-infrared wavelengths.

[0003] Existing microscopes on the market cannot simultaneously meet the technical requirements of long working distance, large numerical aperture, and confocal focus in the visible and near-infrared light bands, so a solution is urgently needed. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, this application proposes a microscope objective and imaging device to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A microscope objective includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side; the first lens group and the third lens group have negative optical power, and the second lens group has positive optical power.

[0007] The first lens group includes a first lens and a second lens arranged sequentially along the optical axis; the first lens is a positive lens and the second lens is a negative lens;

[0008] The second lens group includes a third lens, a fourth lens, a fifth lens 1, and a sixth lens arranged sequentially along the optical axis; the third lens, the fifth lens, and the sixth lens are positive lenses, and the fourth lens is a negative lens;

[0009] The third lens group includes a seventh lens, an eighth lens, a ninth lens, and a tenth lens arranged sequentially along the optical axis; the seventh lens and the ninth lens are negative lenses, and the eighth lens and the tenth lens are positive lenses.

[0010] As a further technical solution of the present invention: the first lens is a biconvex lens; the second lens is a biconcave lens.

[0011] As a further technical solution of the present invention: the third lens is a biconvex lens; the fourth lens is a meniscus lens with its convex surface facing the image side; the fifth lens is a meniscus lens with its convex surface facing the image side; and the sixth lens is a meniscus lens with its convex surface facing the image side.

[0012] As a further technical solution of the present invention: the seventh lens is a biconcave lens; the eighth lens is a biconvex lens; the ninth lens is a meniscus lens with its convex surface facing the image side; and the tenth lens is a meniscus lens with its convex surface facing the image side.

[0013] As a further technical solution of the present invention: the third lens, the fourth lens, and the fifth lens are cemented together to form a cemented triplet lens. The Abbe number of the material of the third lens and the Abbe number of the material of the fifth lens satisfy the following relationship:

[0014] 68 < Vd3 < 72, 68 < Vd5 < 72

[0015] The refractive index and Abbe number of the material of the fourth lens satisfy the following relationships:

[0016] 1.60<Nd4<1.62, 43<Vd4<45

[0017] Wherein, Vd3 is the Abbe number of the material of the third lens, Vd5 is the Abbe number of the material of the fifth lens, Nd4 is the refractive index of the material of the fourth lens, and Vd4 is the Abbe number of the material of the fourth lens.

[0018] As a further technical solution of the present invention: the focal length of the first lens group and the focal length of the third lens group satisfy the following relationship:

[0019] 1.0 < fG3 / fG1 < 1.3

[0020] The focal length of the second lens group and the overall focal length of the microscope objective satisfy the following relationship:

[0021] 0.35 < fG² / f < 0.4

[0022] Wherein, fG3 is the focal length of the third lens group, fG1 is the focal length of the first lens group, fG2 is the focal length of the second lens group, and f is the overall focal length of the microscope objective.

[0023] As a further technical solution of the present invention: the working distance of the microscope objective satisfies the following relationship:

[0024] 27mm≤WD≤30mm

[0025] Wherein, WD is the working distance of the microscope objective, that is, the distance from the object surface to the vertex of the object-side surface of the first lens.

[0026] As a further technical solution of the present invention: the numerical aperture of the microscope objective satisfies the following relationship:

[0027] 0.27≤NA≤0.3

[0028] Wherein, NA is the numerical aperture of the microscope objective.

[0029] As a further technical solution of the present invention: the focal length of the microscope objective satisfies the following relationship:

[0030] 79mm < f < 81mm

[0031] Where f is the overall focal length of the microscope objective.

[0032] As a further technical solution of the present invention: the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all spherical lenses made of glass.

[0033] The present invention also proposes an optical imaging device, including a microscope objective as described above.

[0034] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0035] Compared with existing microscopes of the same magnification, the microscope head of this invention has advantages such as a longer working distance, a larger NA, and a higher resolution; by selecting glass materials with specific refractive indices and Abbe numbers for triple bonding, confocal light and near-infrared light are achieved; the microscope head of this invention can better meet the increasingly diverse and complex demands of the market for microscope heads. Attached Figure Description

[0036] Figure 1 A schematic diagram of the first structure of an embodiment of the microscope objective provided by the present invention;

[0037] Figure 2 This is a second structural schematic diagram of an embodiment of the microscope objective provided by the present invention;

[0038] Figure 3 MTF diagram of the object plane of the microscope objective provided by the present invention in the visible light band of wavelength 435nm~656nm;

[0039] Figure 4 Optical distortion diagram of the object plane of the microscope objective provided by the present invention in the visible light band of wavelength 435nm~656nm;

[0040] Figure 5MTF image of the object plane of the microscope objective provided by the present invention in the near-infrared light band with wavelengths of 750nm~1600nm;

[0041] Figure 6 Optical distortion diagram of the object plane of the microscope objective provided by this invention in the near-infrared light band with wavelengths of 750nm to 1600nm.

[0042] Explanation of icon numbers:

[0043] 100. First lens group; 101. First lens; 102. Second lens;

[0044] 200. Second lens group; 201. Third lens; 202. Fourth lens; 203. Fifth lens; 204. Sixth lens;

[0045] 300. Third lens group; 301. Seventh lens; 302. Eighth lens; 303. Ninth lens; 304. Tenth lens;

[0046] 400, surface of the object;

[0047] 500, Side exit surface. Detailed Implementation

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention proposes a microscope lens that takes into account the lens requirements of a longer working distance, a larger numerical aperture, higher resolution, and confocal coverage in the visible and near-infrared bands, thereby meeting the increasingly diverse and complex demands of the market for lenses.

[0050] Please see Figure 1 In one embodiment of the present invention, the imaging lens includes an object plane 400 arranged sequentially from the object side to the image side, a first lens group 100, a second lens group 200, a third lens group 300, and an image measuring exit surface 500; the first lens group 100 and the third lens group 300 have negative optical power, and the second lens group 200 has positive optical power.

[0051] The first lens group 100 includes a first lens 101 and a second lens 102 arranged sequentially along the optical axis; the first lens 101 is a positive lens and the second lens 102 is a negative lens;

[0052] The second lens group 200 includes a third lens 201, a fourth lens 202, a fifth lens 203, and a sixth lens 204 arranged sequentially along the optical axis; the third lens 201, the fifth lens 203, and the sixth lens 204 are positive lenses, and the fourth lens 202 is a negative lens;

[0053] The third lens group 300 includes a seventh lens 301, an eighth lens 302, a ninth lens 303, and a tenth lens 304 arranged sequentially along the optical axis; the seventh lens 301 and the ninth lens 303 are negative lenses, and the eighth lens 302 and the tenth lens 304 are positive lenses.

[0054] In this embodiment, a longer working distance is achieved through the first lens group 100 with negative optical power; parallel light output is achieved through the third lens group 300 with negative optical power, i.e., the microscope objective is an infinity-corrected microscope objective; a larger numerical aperture is achieved through the reasonable combination of optical power among the first lens group 100, the second lens group 200, and the third lens group 300; and confocal microscopy of the visible light and near-infrared bands of the microscope objective is achieved through the cemented triplet lens (third lens 201, fourth lens 202, and fifth lens 203) located in the second lens group 300, which is made of three glass materials with specific refractive indices and Abbe numbers bonded together.

[0055] More specifically, negative lens groups have the function of diverging light rays; positive lens groups have the function of converging light rays. The diverging effect of the first lens group 100 allows the converging point of light to gradually move away from the lens group, achieving a long working distance. The beam shaping effect of the third lens group 300 corrects the residual aberrations of light after passing through the first two lens groups, making the diverging light rays from the object plane parallel light rays, i.e., the objective lens is an infinity-corrected microscope objective. The reasonable distribution of optical power among the first lens group 100, the second lens group 200, and the third lens group 300 achieves a large numerical aperture. At the same time, a large numerical aperture means higher resolution. By triple-cementing the three lenses of the second lens group 200—the third lens 201, the fourth lens 202, and the fifth lens 203—which are made of glass materials with specific refractive indices and Abbe numbers, the axial and transverse chromatic aberrations of light of different wavelengths are corrected, so that the axial and transverse chromatic aberrations of wavelengths from 435nm to 1700nm are controlled within a good range, achieving confocal light in the visible and near-infrared light bands.

[0056] Therefore, the technical solution of the present invention achieves the advantages of long working distance, large numerical aperture, high resolution, and confocal coverage in the visible and near-infrared bands by reasonably matching the optical power of the first lens group 100, the second lens group 200, and the third lens group 300, and by triple bonding three lenses of materials with specific refractive indices and Abbe numbers (the third lens 201, the fourth lens 202, and the fifth lens 203). This allows the microscope objective of the present invention to better meet the increasingly diverse and complex market demand for microscope objectives.

[0057] Optionally, refer to Figure 1 and Figure 2 The first lens 101 is a biconvex positive lens; the second lens 102 is a biconcave negative lens.

[0058] Optionally, refer to Figure 1 and Figure 2 The third lens 201 is a biconvex positive lens; the fourth lens 202 is a meniscus negative lens, with the convex surface of the fourth lens 202 facing the image-side exit surface 500; the fifth lens 203 is a meniscus positive lens, with the convex surface of the fifth lens 203 facing the image-side exit surface 500; and the sixth lens 204 is a meniscus positive lens, with the convex surface of the sixth lens 204 facing the image-side exit surface 500.

[0059] Optionally, refer to Figure 1 and Figure 2 The seventh lens 301 is a biconcave negative lens; the eighth lens 302 is a biconvex positive lens; the ninth lens 303 is a meniscus negative lens, with the convex surface of the ninth lens 303 facing the image-side exit surface 500; and the tenth lens 304 is a meniscus positive lens, with the convex surface of the tenth lens 304 facing the image-side exit surface 500.

[0060] Among them, the third lens 201, the fourth lens 202, and the fifth lens 203 are cemented together, the seventh lens 301 is cemented together with the eighth lens 302, and the ninth lens 303 is cemented together with the tenth lens 304.

[0061] Optionally, refer to Figure 1 and Figure 2 A cemented triplet lens is formed by cementing the third lens 201, the fourth lens 202, and the fifth lens 203 together. The Abbe number of the material of the third lens 201 and the Abbe number of the material of the fifth lens 203 satisfy the following relationship:

[0062] 68 < Vd3 < 72, 68 < Vd5 < 72

[0063] The refractive index and Abbe number of the material of the fourth lens 202 satisfy the following relationships:

[0064] 1.60<Nd4<1.62, 43<Vd4<45

[0065] Wherein, Vd3 is the Abbe number of the material of the third lens 201, Vd5 is the Abbe number of the material of the fifth lens 203, Nd4 is the refractive index of the material of the fourth lens 202, and Vd4 is the Abbe number of the material of the fourth lens 202.

[0066] Optionally, refer to Figure 1 and Figure 2 The focal lengths of the first lens group 100 and the third lens group 300 satisfy the following relationship:

[0067] 1.0 < fG3 / fG1 < 1.3

[0068] The focal length of the second lens group 200 and the overall focal length of the microscope objective satisfy the following relationship:

[0069] 0.35 < fG² / f < 0.4

[0070] Wherein, fG3 is the focal length of the third lens group 300, fG1 is the focal length of the first lens group 100, fG2 is the focal length of the second lens group 200, and f is the overall focal length of the microscope objective.

[0071] Optionally, refer to Figure 1 and Figure 2 The working distance of a microscope objective satisfies the following relationship:

[0072] 27mm≤WD≤30mm

[0073] Where WD is the working distance of the microscope objective, which is the distance from the object surface to the vertex of the object-side surface of the first lens.

[0074] Optionally, refer to Figure 1 and Figure 2 The numerical aperture of a microscope objective satisfies the following relationship:

[0075] 0.27≤NA≤0.3

[0076] Wherein, NA is the numerical aperture of the microscope objective.

[0077] Optionally, refer to Figure 1 and Figure 2 The focal length of a microscope objective satisfies the following relationship:

[0078] 79mm < f < 81mm

[0079] Where f is the overall focal length of the microscope objective.

[0080] Optionally, refer to Figure 1 and Figure 2The first lens 101, the second lens 102, the third lens 201, the fourth lens 202, the fifth lens 203, the sixth lens 204, the seventh lens 205, the eighth lens 301, the ninth lens 302, and the tenth lens 303 are all spherical lenses made of glass.

[0081] Based on the parameter settings and material combinations of each lens group and lens in the above embodiments, the microscope objectives not only achieve advantages such as a longer working distance, a larger numerical aperture, and higher resolution, but also realize confocal focusing in the visible light and near-infrared bands, thereby further improving the performance of the microscope objectives and broadening their application range.

[0082] Reference Figure 2 In one specific embodiment, the surface curvature radius, thickness, refractive index, Abbe number, and other parameters of each lens included in the microscope head are shown in Table 1. Thickness refers to the distance between the surface of each lens and the surface of the next lens; for example, the thickness of S1 refers to the distance between the center of S1 and the center of S2, i.e., the center thickness of the first lens 101; the thickness of S2 refers to the distance between the center of S2 and the center of S3, i.e., the air thickness between the first lens 101 and the second lens 102.

[0083]

[0084] According to the data in Table 1, the focal length of the microscope objective is f=80mm. If used in conjunction with a tube lens with a focal length of 200mm, the combined magnification is 2.5x. The object-side numerical aperture NA=0.30, working distance WD=30mm, object circle diameter D=4.6mm, fG1=-111.56, fG2=30, and fG3=-130.94. Therefore, Vd3=71.3, Vd5=71.3, Nd4=1.61, Vd4=44.1, fG3 / fG1=1.17, and fG2 / f=0.375. Furthermore, all lenses used in this embodiment are glass spherical lenses. All the above parameters meet the requirements. Specifically, the third lens 201, fourth lens 202, and fifth lens 203 use glass materials with specific Abbe numbers and refractive indices, which can correct chromatic aberration in the visible and near-infrared light bands, achieving confocal focusing of visible and near-infrared light. Based on the above embodiments, the actual test results of the imaging lens are as follows:

[0085] Figure 3 and Figure 5These are the MTF (Modulation Transfer Function) plots of the microscope objectives in the above embodiments for the object plane in the visible light band (435nm~656nm) and for the near-infrared light band (750nm~1600nm), respectively. Figure 3 and Figure 6 It can be seen that the MTF curves of the object plane of the microscope objective are close to the diffraction-limited MTF curves in both the visible and near-infrared bands, which means that confocality in the visible and near-infrared bands is achieved.

[0086] Figure 4 and Figure 6 These are, respectively, the optical distortion images of the object plane of the microscope objectives in the above embodiments under the visible light band with wavelengths of 435nm~656nm and the optical distortion images of the object plane under the near-infrared light band with wavelengths of 750nm~1600nm. According to Figure 4 and Figure 6 It can be seen that the optical distortion of microscope objectives is very small, at 0.0096% in the visible light band and only 0.0018% in the near-infrared light band.

[0087] The present invention also proposes an optical imaging device, which includes a microscope objective. The specific structure of the microscope objective is as described in the above embodiments. Since the optical imaging device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0088] The optical imaging device can be a microscope, projector, scanner, etc. Any device that uses the microscope objective provided in the above embodiments and achieves imaging based on optical imaging technology belongs to the optical imaging device described in this invention.

[0089] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0090] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment have been appropriately combined to form other embodiments that are easy for those skilled in the art to understand.

Claims

1. A microscope objective, characterized in that: It includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side; the first lens group and the third lens group have negative optical power, and the second lens group has positive optical power; The first lens group includes a first lens and a second lens arranged sequentially along the optical axis; the first lens is a positive lens and the second lens is a negative lens; The second lens group includes a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis; the third lens, the fifth lens, and the sixth lens are positive lenses, and the fourth lens is a negative lens; The third lens group includes a seventh lens, an eighth lens, a ninth lens, and a tenth lens arranged sequentially along the optical axis; the seventh lens and the ninth lens are negative lenses, and the eighth lens and the tenth lens are positive lenses; the number of lenses with optical power in the microscope objective is 10. The focal lengths of the first lens group and the third lens group satisfy the following relationship: 1.0 < fG3 / fG1 < 1.3; The focal length of the second lens group and the overall focal length of the microscope objective satisfy the following relationship: 0.35 < fG2 / f < 0.4; Wherein, fG3 is the focal length of the third lens group, fG1 is the focal length of the first lens group, fG2 is the focal length of the second lens group, and f is the overall focal length of the microscope objective.

2. A microscope objective according to claim 1, characterized in that, The first lens is a biconvex lens; the second lens is a biconcave lens.

3. The microscope objective and imaging device according to claim 1, characterized in that, The third lens is a biconvex lens; the fourth lens is a meniscus lens with its convex surface facing the image side; the fifth lens is a meniscus lens with its convex surface facing the image side; and the sixth lens is a meniscus lens with its convex surface facing the image side.

4. A microscope objective according to claim 1, characterized in that, The seventh lens is a biconcave lens; the eighth lens is a biconvex lens; the ninth lens is a meniscus lens with its convex surface facing the image side; and the tenth lens is a meniscus lens with its convex surface facing the image side.

5. A microscope objective according to claim 1, characterized in that, The third, fourth, and fifth lenses are cemented together to form a cemented triplet lens; the Abbe number of the material of the third lens and the Abbe number of the material of the fifth lens satisfy the following relationship: 68<Vd3<72, 68<Vd5<72; The refractive index and Abbe number of the material of the fourth lens satisfy the following relationships: 1.60<Nd4<1.62, 43<Vd4<45; Wherein, Vd3 is the Abbe number of the material of the third lens, Vd5 is the Abbe number of the material of the fifth lens, Nd4 is the refractive index of the material of the fourth lens, and Vd4 is the Abbe number of the material of the fourth lens.

6. A microscope objective according to claim 1, characterized in that, The working distance of a microscope objective satisfies the following relationship: 27mm≤WD≤30mm; Wherein, WD is the working distance of the microscope objective, that is, the distance from the object surface to the vertex of the object-side surface of the first lens; And / or, the numerical aperture of the microscope objective satisfies the following relationship: 0.27≤NA≤0.3; Wherein, NA is the numerical aperture of the microscope objective; And / or, the focal length of the microscope objective satisfies the following relationship: 79mm < f < 81mm; Where f is the overall focal length of the microscope objective; And / or, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are all spherical lenses made of glass.

7. An optical imaging device, characterized in that, Includes the microscope objectives as described in any one of claims 1 to 6.

Images