A 5x dark-field metallurgical objective and metallurgical microscope

Abstract

This invention provides a 5x dark-field metallurgical objective and a metallurgical microscope, relating to the field of microscopy. The 5x dark-field metallurgical objective includes a microscope tube and lenses disposed within the tube. The lenses include a first lens, a second lens, a third lens, and a fourth lens arranged sequentially and spaced apart from the object side to the image side, respectively, and attached to the third lens. The first to fourth lenses are, in sequence, a biconvex lens, a biconcave lens, a plano-convex lens, and a meniscus lens. The microscope tube includes a first end face. The distance between the first lens and the first end face is between 4.1 mm and 4.2 mm, and the distance between the first end face and the object being observed is between 20.8 mm and 20.9 mm. By arranging the first, second, third, and fourth lenses, this invention allows light reflected from the object to pass through only four lenses before being imaged on the eyepiece aperture through the microscope's internal tube diameter, resulting in clear imaging and an increased working distance.

Description

Technical Field

[0001] This invention relates to the field of microscopy, and more specifically, to a 5x dark-field metallurgical objective lens and a metallurgical microscope. Background Technology

[0002] Microscopes are commonly used experimental instruments in modern science. High-magnification and high-precision microscopes often require complex imaging systems. Dark-field objective lenses of the imaging system have various magnifications. Currently, there are many high-quality metallurgical objective lenses, and the high requirements for glass materials result in high costs. Moreover, the existing 5x dark-field metallurgical objective lens has a short working distance, and the received incident light cannot be fully utilized. When observing in the dark field of a large field-of-view microscope, the brightness of the field of view is uneven, resulting in poor imaging effects. Summary of the Invention

[0003] The problem this invention aims to solve is how to improve imaging quality during dark-field observation.

[0004] Therefore, the present invention provides a 5x dark-field metallurgical objective lens, comprising a lens barrel and a lens, wherein the lens is disposed within the lens barrel, and the lens comprises a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side, the first lens, the second lens, and the third lens being spaced apart, the first lens being a biconvex lens, the second lens being a biconcave lens, the third lens being a plano-convex lens, and the fourth lens being a meniscus lens, wherein the convex surface of the third lens is fitted to the concave surface of the fourth lens, the lens barrel comprising a first end face facing the object side, the distance between the first lens and the first end face being between 4.1 mm and 4.2 mm, and in use, the distance between the first end face and the observed object being between 20.8 mm and 20.9 mm.

[0005] Optionally, the distance from the center of the convex surface of the first lens facing the second lens to the center of the concave surface of the second lens facing the first lens is 3.5 mm.

[0006] Optionally, the distance from the center of the concave viewing surface of the second lens to the center of the convex viewing surface of the third lens is 4.2 mm.

[0007] Optionally, the refractive index of the first lens is 1.516798, and the Abbe number of the first lens is 64.198258.

[0008] Optionally, the refractive index of the second lens is 1.578420, and the Abbe number of the second lens is 41.113120.

[0009] Optionally, the refractive index of the third lens is 1.556709, and the Abbe number of the third lens is 58.649202.

[0010] Optionally, the refractive index of the fourth lens is 1.698949, and the Abbe number of the fourth lens is 30.065686.

[0011] Optionally, the lens barrel includes an inner barrel, an outer barrel, and a reflective surface. The inner barrel and the outer barrel are coaxially arranged. The inner barrel is sleeved on the peripheral surface of the lens. The inner barrel and the outer barrel form an incident light channel. The reflective surface is connected to the outer barrel. The angle between the reflective surface and the incident light channel is between 8.5 degrees and 8.6 degrees.

[0012] Compared with existing technologies, the beneficial effects of the 5x dark-field metallurgical objective lens of this invention are:

[0013] This invention employs a first lens, a second lens, a third lens, and a fourth lens, arranged coaxially from the object side to the image side, with the first, second, and third lenses spaced apart and the third and fourth lenses fitted together. The first lens is a biconvex lens, the second lens a biconcave lens, the third lens a plano-convex lens, and the fourth lens a meniscus lens. The convex surface of the third lens is fitted to the concave surface of the fourth lens. The lens barrel includes a first end face facing the object side, and the first lens is connected to the inner side of the lens barrel. The distance between the first end face and the first lens is between 4.1 and 4.2 mm. When the objective lens is working, the distance between the first end face and the observed object is between 20.8 and 20.9 mm. The long working distance improves the applicability of the 5x dark field metallurgical objective lens. In large field-view microscopic dark field observation, the light reflected from the observed object 9 only passes through the first lens, the second lens, the third lens, and the fourth lens. These four lenses can then pass through the internal diameter of the microscope to form an image on the eyepiece aperture. The image is clear and of high quality, which reduces the number of lenses required for the lens and lowers the manufacturing cost of the 5x dark field metallurgical objective lens.

[0014] The present invention also provides a metallurgical microscope, including the above-described 5x dark-field metallurgical objective lens.

[0015] Compared with the prior art, the metallurgical microscope provided by the present invention has roughly the same technical effect as the above-mentioned 5x dark-field metallurgical objective lens, and will not be described in detail here. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the lens structure according to an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of the 5x dark-field metallurgical objective lens according to an embodiment of the present invention;

[0018] Figure 3This is the image quality evaluation transfer function of the 5x dark-field metallurgical objective lens described in this embodiment of the invention.

[0019] Explanation of reference numerals in the attached figures:

[0020] 1-First lens; 2-Second lens; 3-Third lens; 4-Fourth lens; 5-Inner cylinder; 6-Outer cylinder; 7-Reflecting surface; 8-First end face; 9-Object being observed. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] It should be noted that in the description of this disclosure, the orientation or positional relationship indicated by terms such as "up", "down", "left", "right", "top", "bottom", "front", "back", "inner" and "outer" is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this disclosure, and is not intended to indicate or imply that the device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0024] Furthermore, although the invention has been described with reference to specific embodiments in this disclosure, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways not used as described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

[0025] To solve the above problems, such as Figure 1 and Figure 2As shown, the present invention provides a 5x dark-field metallurgical objective lens, including a lens barrel and a lens. The lens is disposed inside the lens barrel. The lens includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 arranged sequentially from the object side to the image side. The first lens 1, the second lens 2, and the third lens 3 are spaced apart. The first lens 1 is a biconvex lens, the second lens 2 is a biconcave lens, the third lens 3 is a plano-convex lens, and the fourth lens 4 is a meniscus lens. The convex surface of the third lens 3 is fitted to the concave surface of the fourth lens 4. The lens barrel includes a first end face 8 facing the object side. The distance between the first lens 1 and the first end face 8 is between 4.1 mm and 4.2 mm. In use, the distance between the first end face 8 and the observed object 9 is between 20.8 mm and 20.9 mm.

[0026] In this embodiment, a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 are arranged sequentially from the object side to the image side, coaxially positioned, with the first lens 1, second lens 2, and third lens 3 spaced apart. The third lens 3 and the fourth lens 4 are fitted together. The first lens 1 is a biconvex lens, the second lens 2 is a biconcave lens, the third lens 3 is a plano-convex lens, and the fourth lens 4 is a meniscus lens. The convex surface of the third lens 3 is fitted together with the concave surface of the fourth lens 4. The lens barrel includes a first end face 8 facing the object side. The first lens 1 is connected to the lens... Inside the tube, the distance between the first end face 8 and the first lens 1 is between 4.1 and 4.2 mm. When the objective lens is working, the distance between the first end face 8 and the observed object 9 is between 20.8 and 20.9 mm. The long working distance improves the applicability of the 5x dark-field metallurgical objective lens. In large-field microscopic dark-field observation, the light reflected from the observed object 9 only passes through the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4. These four lenses can then be imaged on the eyepiece aperture through the tube diameter inside the microscope. The image is clear and of high quality, which reduces the number of lenses required for the lens and lowers the manufacturing cost of the 5x dark-field metallurgical objective lens.

[0027] Specifically, the first lens 1 is configured as a biconvex lens, with an object-side radius of 11.422 mm, an image-side radius of 21.786 mm, a center-to-center distance of 5.5 mm, and a radial cross-sectional diameter of 8 mm. The second lens 2 is configured as a biconcave lens, with an object-side radius of 8.7 mm, an image-side radius of 13.963 mm, a center-to-center distance of 2 mm, and a radial cross-sectional diameter of 5.746 mm. The third lens 3 is configured as a plano-convex lens, with an image-side radius of 7.838 mm. The distance between the centers of the two mirror surfaces is 2 mm. The radial cross-sectional diameter of the third lens 3 is 6.6 mm. The fourth lens 4 is set as a meniscus lens. The radius of the fourth lens 4 facing the object side is 7.838 mm, and the radius of the fourth lens 4 facing the image side is 121.121 mm. The distance between the centers of the two mirror surfaces of the fourth lens 4 is 3.3 mm, and the radial cross-sectional diameter of the fourth lens 4 is 6.74 mm. By designing the shapes and dimensions of the first lens 1, second lens 2, third lens 3, and fourth lens 4 as described above, the light reflected from the observed object 9 is refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam. This makes the conjugate distance of the objective lens infinitely far, facilitating the projection of the parallel beam refracted from the fourth lens 4 onto the eyepiece. Furthermore, the radius of the third lens 3 facing the image side is the same as the radius of the fourth lens 4 facing the object side, facilitating the fit between the convex surface of the third lens 3 and the concave surface of the fourth lens 4.

[0028] Specifically, when the distance between the first end face 8 and the first lens 1 is 4.14 mm and the distance between the observed object 9 and the first end face 8 is 20.86 mm, the eyepiece image is clearest and the imaging effect is best. The diameter of the observed object 9 needs to be around 5 mm, for example, 4.82 mm.

[0029] Optionally, the distance from the center of the convex surface of the first lens 1 facing the second lens 2 to the center of the concave surface of the second lens 2 facing the first lens 1 is 3.5 mm.

[0030] In this embodiment, by setting the distance from the center of the convex surface of the first lens 1 facing the second lens 2 to the center of the concave surface of the second lens 2 facing the first lens 1 to 3.5 mm, the light reflected from the observed object 9 is refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam, making the conjugate distance of the objective lens infinitely far, so that the parallel beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0031] Optionally, the distance from the center of the concave surface of the second lens 2 to the center of the convex surface of the third lens 3 is 4.2 mm.

[0032] In this embodiment, by setting the distance from the center of the concave transparent surface of the second lens 2 to the center of the convex transparent surface of the third lens 3 to 4.2 mm, the light reflected from the observed object 9 is refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam, making the conjugate distance of the objective lens infinitely far, so that the parallel beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0033] Optionally, the refractive index of the first lens 1 is 1.516798, and the Abbe number of the first lens 1 is 64.198258.

[0034] In this embodiment, by setting the refractive index of the first lens 1 to 1.516798 and the Abbe number to 64.198258, it is convenient for the light reflected by the observed object 9 to be refracted by the first lens 1 and then illuminate the second lens 2. It is also convenient for the light reflected by the observed object 9 to be refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam. This makes the conjugate distance of the objective lens infinitely far, so that the parallel beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0035] Optionally, the refractive index of the second lens 2 is 1.578420, and the Abbe number of the second lens 2 is 41.113120.

[0036] In this embodiment, by setting the refractive index of the second lens 2 to 1.578420 and the Abbe number to 41.113120, it is convenient for the light reflected by the observed object 9 to be refracted by the second lens 2 and then illuminate the third lens 3. It is also convenient for the light reflected by the observed object 9 to be refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam. This makes the conjugate distance of the objective lens infinitely far, so that the parallel beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0037] Optionally, the refractive index of the third lens 3 is 1.556709, and the Abbe number of the third lens 3 is 58.649202.

[0038] In this embodiment, by setting the refractive index of the third lens 3 to 1.556709 and the Abbe number to 58.649202, it is convenient for the light reflected by the observed object 9 to be refracted by the third lens 3 and then illuminate the fourth lens 4. It is also convenient for the light reflected by the observed object 9 to be refracted by the first lens 1 to the fourth lens 4 and emitted as a parallel beam. This makes the conjugate distance of the objective lens infinitely far, so that the parallel beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0039] Optionally, the refractive index of the fourth lens 4 is 1.698949, and the Abbe number of the fourth lens 4 is 30.065686.

[0040] In this embodiment, by setting the refractive index of the fourth lens 4 to 1.698949 and the Abbe number to 30.065686, the light reflected from the observed object 9 is refracted by the fourth lens 4 and becomes parallel light, making the conjugate distance of the objective lens infinitely far, so that the parallel light beam refracted from the fourth lens 4 can be projected onto the eyepiece.

[0041] Optionally, such as Figure 2 As shown, the lens barrel includes an inner barrel 5, an outer barrel 6, and a reflective surface 7. The inner barrel 5 and the outer barrel 6 are coaxially arranged. The inner barrel 5 is sleeved on the peripheral surface of the lens. The inner barrel 5 and the outer barrel 6 form an incident light channel. The reflective surface 7 is connected to the outer barrel 6. The angle between the reflective surface 7 and the incident light channel is between 8.5 degrees and 8.6 degrees.

[0042] In this embodiment, the outer cylinder 6 and the inner cylinder 5 are coaxially arranged, and the lens is set inside the inner cylinder 5. The inner surface of the inner cylinder 5 is connected to the peripheral surfaces of the first lens 1, the second lens 2, the third lens 3, and the fourth lens 4. The gap between the inner cylinder 5 and the outer cylinder 6 is the incident light channel. A reflecting surface 7 is provided and connected to the inner surface of the outer cylinder 6. The connection method can be bolt connection. The angle between the mirror surface of the reflecting surface 7 and the incident light channel on the axial section is between 8.5 degrees and 8.6 degrees. This angle can ensure that the incident light enters from the incident light channel. After being reflected by the reflecting surface 7, the incident light can be fully illuminated on the observed object 9, thereby improving the clarity of the eyepiece imaging.

[0043] Specifically, the eyepiece image is clearest when the angle between the reflective surface 7 and the incident light channel on the axial section is 8.53 degrees. Setting the incident light channel to 2.49 mm ensures that the incident light enters through the incident light channel, and after reflection by the reflective surface 7, the incident light can completely illuminate the observed object 9, thereby improving the clarity of the eyepiece image. The numerical aperture of the objective lens can be 0.12 mm.

[0044] In summary, combining Figure 3 As shown, the curves above represent the transfer functions at the field of view points of 0mm, 5.5mm, 8mm, 10mm, 11mm and the diffraction limit, respectively. It can be seen that the transfer function of the embodiment of the present invention at any field of view point is close to the transfer function at the diffraction limit, and the imaging is clear.

[0045] The present invention also provides a metallurgical microscope, including the above-described 5x dark-field metallurgical objective lens.

[0046] The metallurgical microscope and the 5x dark-field metallurgical objective lens described in this invention have the same advantages over the prior art, and will not be repeated here.

[0047] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A 5x dark-field metallurgical objective lens, characterized in that, The system includes a lens barrel and a lens. The lens is disposed inside the lens barrel. The lens includes a first lens (1), a second lens (2), a third lens (3), and a fourth lens (4) arranged sequentially from the object side to the image side. The first lens (1), the second lens (2), and the third lens (3) are spaced apart. The first lens (1) is a biconvex lens, the second lens (2) is a biconcave lens, the third lens (3) is a plano-convex lens, and the fourth lens (4) is a meniscus lens. The convex surface of the third lens (3) is fitted to the concave surface of the fourth lens (4). The lens barrel includes a first end face (8) facing the object side. The distance between the first lens (1) and the first end face (8) is between 4.1 mm and 4.2 mm. In use, the first end face (8) is close to the object being observed (9). The distance between the two lenses is between 20.8 mm and 20.9 mm. The distance from the center of the convex surface of the first lens (1) facing the second lens (2) to the center of the concave surface of the second lens (2) facing the first lens (1) is 3.5 mm. The distance from the center of the concave surface of the second lens (2) facing the third lens (3) to the center of the convex surface of the third lens (3) is 4.2 mm. The lens barrel includes an inner barrel (5), an outer barrel (6) and a reflective surface (7). The inner barrel (5) and the outer barrel (6) are coaxially arranged. The inner barrel (5) is sleeved on the peripheral surface of the lens. The inner barrel (5) and the outer barrel (6) form an incident light channel. The reflective surface (7) is connected to the outer barrel (6). The angle between the reflective surface (7) and the incident light channel is between 8.5 degrees and 8.6 degrees.

2. The 5x dark-field metallurgical objective lens according to claim 1, characterized in that, The refractive index of the first lens (1) is 1.516798, and the Abbe number of the first lens (1) is 64.198258.

3. The 5x dark-field metallurgical objective lens according to claim 1, characterized in that, The refractive index of the second lens (2) is 1.578420, and the Abbe number of the second lens (2) is 41.113120.

4. The 5x dark-field metallurgical objective lens according to claim 1, characterized in that, The refractive index of the third lens (3) is 1.556709, and the Abbe number of the third lens (3) is 58.649202.

5. The 5x dark-field metallurgical objective lens according to claim 1, characterized in that, The refractive index of the fourth lens (4) is 1.698949, and the Abbe number of the fourth lens (4) is 30.065686.

6. A metallurgical microscope, characterized in that, Includes the 5x dark-field metallurgical objective lens as described in any one of claims 1 to 5.

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