Microobjective

Abstract

The invention relates to a microscope objective, which comprises a first lens group, a second lens group and a third lens group which are sequentially arranged from an object end to an image end along an optical axis direction. A lens combination is formed by a first lens group with positive focal power, a second lens group with positive focal power and a third lens group with negative focal power, and each of the second lens group and the third lens group at least comprises one positive focal power lens with the Abbe number larger than 80. The third lens group adopts negative focal power, so that the light transmitted by the front two groups of lenses can be reasonably corrected, the offset of the edge light under a large field of view is compensated, and the effective imaging field of view of the objective lens is effectively expanded; high-Abbe-number positive-focal-power lenses are introduced into the second lens group and the third lens group, so that the problems of aberration, imaging blurring and the like which are easy to occur under the conditions of large view field and long working distance are solved. Therefore, the microscope objective provided by the invention can improve the imaging quality under the requirement of a large field of view, and meets the requirement of a digital imaging technology on the microscope objective.

Description

Technical Field

[0001] This application belongs to the field of optical technology, and in particular relates to a microscope objective. Background Technology

[0002] Traditional microscopy systems rely on human eye observation, and their image-side field of view must be adapted to the optimal viewing angle of the human eye, typically not exceeding ⌀26.5mm. With the continuous development of digital imaging technology, the market has placed more comprehensive and precise demands on the collection of detailed specimen information, but traditional microscopy systems, limited by the aforementioned field of view bottleneck, can no longer meet these requirements.

[0003] To address this pain point, existing technological improvements have not pointed to a technical route for expanding the field of view, and have failed to break through the inherent bottlenecks of traditional designs; even the few solutions that attempt to expand the field of view of microscope objectives suffer from poor imaging results and cannot fundamentally solve the core problem of limited field of view. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a microscope objective that addresses the shortcomings of existing microscope objectives in scenarios requiring a large field of view.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A microscope objective includes components arranged sequentially from the object end to the image end along the optical axis:

[0007] A first lens group, the first lens group having positive optical power;

[0008] The second lens group has positive power and includes at least one lens with an Abbe number greater than 80.

[0009] The third lens group has negative optical power and includes at least one lens with positive optical power and an Abbe number greater than 80.

[0010] Preferably, in the microscope objective of the present invention, the second lens group includes, along the optical axis from the object end to the image end, a second lens with positive optical power and a third lens with positive optical power.

[0011] Preferably, in the microscope objective of the present invention, the second lens is a single lens and the third lens is a cemented lens.

[0012] Preferably, in the microscope objective of the present invention, the third lens group includes, along its optical axis from the object end to the image end, a fourth lens with positive optical power and a fifth lens with negative optical power.

[0013] Preferably, in the microscope objective of the present invention, the fourth lens is a cemented doublet lens, comprising a first surface, a second surface and a third surface, wherein the center of the third surface is located on the side closer to the image end.

[0014] Preferably, in the microscope objective of the present invention, the fifth lens is a cemented doublet lens, comprising a fourth surface, a fifth surface and a sixth surface, wherein the center of the fourth surface is located on the side closer to the object end.

[0015] Preferably, in the microscope objective of the present invention, the first lens group includes a first lens, the first lens is a cemented triplet lens, and the centers of the two cemented surfaces of the first lens are both located on the side closer to the object end.

[0016] Preferably, the microscope objective of the present invention satisfies the following:

[0017] 1 <f2 / f<4;

[0018] -15 <f3 / f<-5;

[0019] f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f is the focal length of the microscope objective.

[0020] Preferably, the microscope objective of the present invention satisfies the following:

[0021] 4 <f1 / f<7;

[0022] f1 is the focal length of the first lens group.

[0023] Preferably, the microscope objective of the present invention satisfies the following:

[0024] 3 <TTL / f<8;

[0025] TTL is the total optical length of the microscope objective.

[0026] The beneficial effects of this invention are as follows: A lens assembly is formed by a first lens group with positive optical power, a second lens group with positive optical power, and a third lens group with negative optical power. Both the second and third lens groups contain at least one lens with an Abbe number greater than 80 and positive optical power. The third lens group, with its negative optical power, can reasonably correct the light transmitted by the first two lens groups, compensating for the offset of edge light rays under a large field of view, and effectively expanding the effective imaging field of view of the objective lens. The introduction of high Abbe number positive optical power lenses in the second and third lens groups solves problems such as aberrations and image blurring that easily occur under large fields of view and long working distances. Therefore, the microscope objective of this invention can improve the imaging quality under large field of view requirements and meet the requirements of digital imaging technology for microscope objectives. Attached Figure Description

[0027] The technical solution of this application will be further described below with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of the microscope objective structure according to an embodiment of this application;

[0029] Figure 2 This is a field curvature diagram of a microscope objective lens according to an embodiment of this application;

[0030] Figure 3 This is a distortion diagram of a microscope objective lens according to an embodiment of this application;

[0031] Figure 4 This is a chromatic aberration diagram of a microscope objective lens according to an embodiment of this application.

[0032] The attached figures are labeled as follows:

[0033] 100: First lens group;

[0034] 1: First lens; 11: Seventh surface; 12: Eighth surface; 13: Ninth surface; 14: Tenth surface;

[0035] 200: Second lens group;

[0036] 2: Second lens; 21: Eleventh surface; 22: Twelfth surface;

[0037] 3: Third lens; 31: Thirteenth surface; 32: Fourteenth surface; 33: Fifteenth surface;

[0038] 300: Third lens group;

[0039] 4: Fourth lens; 41: First surface; 42: Second surface; 43: Third surface;

[0040] 5: Fifth lens; 51: Fourth surface; 52: Fifth surface; 53: Sixth surface. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0042] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In the accompanying drawings, for clarity, the length, area, volume, gap dimensions, and relative dimensions of components, as well as the included angles and relative positional relationships between components, may be exaggerated. The same reference numerals denote the same elements throughout the drawings.

[0045] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] This embodiment provides a microscope objective, such as... Figure 1 As shown, it includes a first lens group 100, a second lens group 200 and a third lens group 300 arranged sequentially from the object end to the image end along the optical axis.

[0047] The first lens group 100 has positive optical power; the second lens group 200 has positive optical power, and the second lens group 200 includes at least one lens with positive optical power and an Abbe number greater than 80; the third lens group 300 has negative optical power, and the third lens group 300 includes at least one lens with positive optical power and an Abbe number greater than 80.

[0048] The microscope objective provided in this embodiment forms a lens assembly consisting of a first lens group 100 with positive optical power, a second lens group 200 with positive optical power, and a third lens group 300 with negative optical power. Both the second lens group 200 and the third lens group 300 contain at least one lens with an Abbe number greater than 80 and positive optical power. The third lens group, employing negative optical power, can reasonably correct the light transmitted by the first two lens groups, compensating for the offset of light rays at the edges of a large field of view and effectively expanding the effective imaging field of view of the objective. The introduction of high Abbe number positive optical power lenses in the second lens group 200 and the third lens group 300 solves problems such as aberrations and image blurring that easily occur under large fields of view and long working distances. Therefore, the microscope objective of this invention can improve the imaging quality under large field of view requirements and meet the requirements of digital imaging technology for microscope objectives.

[0049] In an optional embodiment, the second lens group 200 includes, from the object end to the image end along the optical axis, a second lens 2 with positive optical power and a third lens 3 with positive optical power. The second lens 2 and the third lens 3 work together to converge light, efficiently transmit the large field-of-view light received by the first lens group 100, ensure the light utilization rate of large field-of-view imaging, and correct chromatic aberration to the greatest extent possible while bearing the main light refraction.

[0050] In an optional embodiment, the second lens 2 is a single lens, and the third lens 3 is a cemented lens. In this embodiment, the single lens simplifies the structure and reduces the difficulty of processing and assembly, while the cemented lens can accurately correct aberrations. The combination of the two satisfies the core requirement of double positive optical power while also taking into account structural practicality and imaging accuracy, thus meeting the overall design goal of low distortion and high definition.

[0051] In an optional embodiment, the third lens group 300 includes, along its optical axis from the object end to the image end, a fourth lens 4 with positive optical power and a fifth lens 5 with negative optical power. In this embodiment, the fourth lens 4 and the fifth lens 5 work together to achieve the negative optical power requirement of the third lens group 300. The fourth lens 4 receives the light transmitted from the previous group (the second lens group 200) and performs preliminary calibration. The fifth lens 5 further corrects aberrations and compensates for light shift under a large field of view through its negative optical power, while also connecting the overall optical axis to ensure imaging effects with long working distances and low distortion, thus adapting to the overall system design.

[0052] In an optional embodiment, the fourth lens 4 is a doublet lens, including a first surface 41, a second surface 42, and a third surface 43. The center position of the third surface 43 is on the side close to the image end. The doublet lens can accurately correct chromatic aberration and spherical aberration. With the curved surface design of the three surfaces and the center position of the third surface, it optimizes the light receiving and propagation paths, enabling the fourth lens 4 to more stably receive the light transmitted by the second lens group and complete preliminary calibration. Furthermore, it cooperates with the fifth lens 5 to achieve the negative optical power requirement of the third lens group, further improving the aberration correction accuracy, compensating for the light shift in a large field of view, maintaining the stability of the optical axis, and ensuring the imaging effect of the system with a long working distance and low distortion.

[0053] In an optional embodiment, the fifth lens 5 is a doublet lens, including a fourth surface 51, a fifth surface 52, and a sixth surface 53. The center position of the fourth surface 51 is on the side close to the object end. The center position design of the fourth surface 51 adapts to the light path transmitted by the fourth lens 4, optimizes the light emission angle, helps the fifth lens 5 give full play to the role of negative optical power, cooperates with the fourth lens 4 to stabilize the optical axis, further compensates for the light shift in a large field of view, and ensures the imaging clarity and low distortion performance of the system.

[0054] In an optional embodiment, the first lens group 100 includes a first lens 1. The first lens 1 is a triplet lens, and the center positions of the two cemented surfaces (the eighth surface 12 and the ninth surface 13) of the first lens 1 are both on the side close to the object end. The triplet lens can efficiently correct the chromatic aberration and spherical aberration of the incident light at the object end. The design of the two cemented surfaces with the centers close to the object end adapts to the light path of the object surface, can stably receive the light emitted from the object surface within a large field of view, reduce the initial light propagation deviation, lay a foundation for transmitting light to the subsequent second lens group 200 and third lens group 300, and at the same time assist in maintaining the stability of the overall optical axis.

[0055] In an optional embodiment, the microscope objective satisfies: 1 < f2 / f < 4; -15 < f3 / f < -5; f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f is the focal length of the microscope objective. Limiting the focal lengths of the second lens group 200 and the third lens group 300 of the microscope objective can better balance various aberrations.

[0056] In an optional embodiment, the microscope objective satisfies: 4 < f1 / f < 7; f1 is the focal length of the first lens group. Limiting the focal length of the first lens group 100 of the microscope objective ensures that the objective has a long working distance.

[0057] In an optional embodiment, the microscope objective satisfies: 3 < TTL / f < 8; TTL is the overall optical length of the microscope objective. Limiting the focal length and the overall optical length of the microscope objective ensures the rationality of the designed objective in terms of physical size.

[0058] This embodiment provides an example of the parameters of each optical component of a microscope objective, satisfying the conditions in Table 1. Wherein, R is the radius of curvature of the optical surface of each lens, D is the axial distance from the corresponding optical surface to the next optical surface, Nd is the refractive index of the corresponding lens for d-rays (wavelength 587nm), and Vd is the Abbe number of the d-ray in the corresponding lens. The second lens 2, the third lens 3, and the fourth lens 4 are positive power lenses with an Abbe number greater than 80. The second lens group 200 must contain at least one positive power lens with an Abbe number greater than 80, and the third lens group 300 must contain at least one positive power lens with an Abbe number greater than 80.

[0059] Table 1

[0060]

[0061] The field curvature, distortion, and spherical aberration of the microscope objective in this embodiment are as follows: Figures 2-4 As shown.

[0062] Figure 2 In the figure, curves T and S represent the meridional field curvature characteristic curve and the sagittal field curvature characteristic curve, respectively. The T and S curves almost completely overlap, indicating minimal astigmatism (TS). Astigmatism is a significant aberration causing blurring of image points in different directions; the smaller the astigmatism, the better the isotropy of the image. The horizontal axis represents the field curvature value (unit: μm), and the vertical axis represents the field height (range ±10, corresponding to a larger field of view). As can be seen from the figure, the maximum shift in field curvature across the entire field does not exceed 1 μm, and the change is gradual, indicating excellent field curvature correction and minimal image plane curvature, demonstrating excellent image quality.

[0063] Figure 3 In the figure, the curve represents the distortion characteristics. The horizontal axis represents the percentage of distortion, and the vertical axis represents the field of view height. As can be seen from the figure, the maximum absolute value of distortion across the entire field does not exceed 0.1% (i.e., 0.001), and the distortion approaches zero near the center of the field of view, with a gradual change in distortion at the edges. The curve is generally biased towards the negative direction, exhibiting barrel distortion, but the value is extremely small and its impact on imaging accuracy is negligible. The maximum distortion is only 0.1%, and it is evenly distributed across the entire field, demonstrating excellent distortion performance.

[0064] Figure 4In the diagram, the microscope objectives are shown to have aberration curves observed for the F-line (wavelength 486 nm), d-line (wavelength 587 nm), and C-line (wavelength 656 nm). The horizontal axis represents the aberration shift (unit: mm), and the vertical axis represents the field of view height. Throughout the entire field, the maximum aberration shift of the three curves does not exceed 0.012 mm (12 μm), and the aberration approaches zero near the center of the field of view, with gentle changes in edge aberration, indicating excellent overall aberration control. The F, d, and C curves almost completely overlap, and the aberration differences between different wavelengths of light are extremely small. This means that the secondary spectrum (the core indicator of chromatic aberration) is effectively suppressed, and chromatic aberration correction achieves extremely high precision.

[0065] As can be seen, the microscope objective of this embodiment forms a lens assembly by setting a first lens group 100 with positive optical power, a second lens group 200 with positive optical power, and a third lens group 300 with negative optical power. Both the second lens group 200 and the third lens group 300 contain at least one lens with a positive optical power and an Abbe number greater than 80. This achieves effects such as a large field of view, low distortion, and a long working distance, thereby improving the imaging quality of the large field-of-view microscope objective.

[0066] Based on the above-described preferred embodiments according to this application, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this application. The technical scope of this application is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A microscope objective, characterized in that, Including those arranged sequentially from the object end to the image end along the optical axis: The first lens group (100) has positive optical power; The second lens group (200) has positive power and includes at least one lens with an Abbe number greater than 80. The third lens group (300) has negative optical power and includes at least one lens with positive optical power and an Abbe number greater than 80.

2. The microscope objective according to claim 1, characterized in that, The second lens group (200) includes a second lens (2) with positive optical power and a third lens (3) with positive optical power in sequence from the object end to the image end along the optical axis.

3. The microscope objective according to claim 2, characterized in that, The second lens (2) is a single lens, and the third lens (3) is a cemented lens.

4. The microscope objective according to claim 1, characterized in that, The third lens group (300) includes, along its optical axis from the object end to the image end, a fourth lens (4) with positive optical power and a fifth lens (5) with negative optical power.

5. The microscope objective according to claim 4, characterized in that, The fourth lens (4) is a cemented doublet lens, comprising a first surface (41), a second surface (42) and a third surface (43), wherein the center of the third surface (43) is located on the side closer to the image end.

6. The microscope objective according to claim 5, characterized in that, The fifth lens (5) is a cemented doublet lens, comprising a fourth surface (51), a fifth surface (52) and a sixth surface (53), with the center of the fourth surface (51) located on the side closest to the object end.

7. The microscope objective according to claim 1, characterized in that, The first lens group (100) includes a first lens (1), which is a cemented lens, and the centers of the two cemented surfaces of the first lens (1) are located on the side closer to the object end.

8. The microscope objective according to any one of claims 1-7, characterized in that, The microscope objective satisfies: 1 <f2 / f<4; -15 <f3 / f<-5; f2 is the focal length of the second lens group, f3 is the focal length of the third lens group, and f is the focal length of the microscope objective.

9. The microscope objective according to claim 8, characterized in that, The microscope objective satisfies: 4 <f1 / f<7; f1 is the focal length of the first lens group.

10. The microscope objective according to claim 8, characterized in that, The microscope objective satisfies: 3 <TTL / f<8; TTL is the total optical length of the microscope objective.

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