A long working distance large field of view magnification switchable microscopic objective applied to liquid internal object measurement

Abstract

The application discloses a long-object-distance large-view-field magnification switchable microscopic objective applied to liquid internal object measurement and relates to the field of microscopes, which comprises optical components of a 5-fold microscopic objective and optical components of a 10-fold microscopic objective combined with a sub-lens assembly, the magnification switching under 5-fold and 10-fold is realized by switching the sub-lens assembly, the long-object-distance large-view-field advantages are achieved, the optical length is unchanged during the magnification switching, the operation is simple during the application to microscopic observation, the microscopic observation on the objects in the liquid environment can be realized, the transmission characteristic is good, the resolution in the whole view field is high, and the distortion is small.

Description

Technical Field

[0001] This invention relates to the field of microscopy, specifically to a long-distance, large-field-of-view, switchable-magnification microscope objective for measuring objects in liquids. Background Technology

[0002] Microscope objectives are crucial optical components in optical microscopes, playing a primary role in magnifying objects and thus influencing image quality and various optical parameters. Today, objectives are used in numerous fields, including: biology for observing microorganisms, cells, and bacteria; semiconductors for microfabrication using photolithography; real-time monitoring of fiber optic fusion splicers; high-precision optical inspection of high-resolution circuit patterns; crystal processing; precision inspection of lens and prism surface quality; and holographic imaging. With technological advancements, higher demands are placed on objective specifications. Research-grade microscopes and industrial inspection applications require objectives with high precision and minimal aberrations over a wide field of view.

[0003] In special cases, such as when the sample is immersed in a deep liquid environment, when detecting microstructures in a liquid environment, or when the sample is large and needs to be completely submerged, these measurement conditions result in a long distance between the sample and the objective lens. Furthermore, the immersion of the sample in the liquid environment introduces a certain amount of aberrations. To achieve precise measurement of samples of different sizes, it is necessary to switch between different magnifications without changing the overall system length. For traditional objective lens designs, magnification is related to both object distance and image distance, meaning a trade-off must be made between system length and magnification. Therefore, achieving a longer object distance, higher resolution, immersion measurement, rapid switching between different magnifications without changing the overall length, and lens miniaturization are problems that need to be solved. Since the sample is completely immersed in the liquid environment, a forward optical path is used in the lens design, which more closely reflects the actual usage environment.

[0004] Existing microscope objectives, such as those published in patent documents "CN 110824682 A" and "CN 114460733 A", disclose a microscope imaging objective for fiber optic fusion splicer core identification and its imaging method, as well as a microscope objective for fiber optic fusion splicers with higher magnification. These two objectives achieve 5x and 20x magnification respectively, and both lenses exhibit good imaging characteristics, achieving high-precision imaging with a large field of view. However, the object distance and overall length of the two lenses differ, requiring adjustments to the installation and imaging positions in practical use. The maximum field of view for both lenses is 2.5mm, necessitating a larger field of view. Patent document "CN 114895434 A" discloses a long-object-distance linear dispersion objective, with an object distance greater than 80mm, but it lacks imaging capabilities for liquid-immersed samples, and the system does not offer magnification. Therefore, a new technical solution is needed to address the problem of high-precision measurement with switchable magnification in liquid-immersed sample environments and with a fixed optical path length. Summary of the Invention

[0005] The purpose of this invention is to provide a long-distance, large-field-of-view, switchable-magnification microscope objective for measuring objects in liquids, which can achieve lens miniaturization while meeting the requirements of long distance, high precision, and liquid immersion measurement.

[0006] One objective of this invention is to provide an optical component for a 5x objective lens, comprising: a main lens, wherein the main lens has the following structure:

[0007] From the object plane to the image plane, the lenses are, in order, a meniscus lens, a first cemented doublet, a second cemented doublet, and a plano-convex lens;

[0008] The first surface of the meniscus lens is convex, and the second surface is concave.

[0009] The first cemented doublet lens is a combination of a first lens and a second lens arranged sequentially from the object plane to the image plane. The third and fourth surfaces of the first lens are both convex, and the fifth and sixth surfaces of the second lens are both concave, with the fourth and fifth surfaces bonded together.

[0010] The second cemented doublet lens is composed of a third lens and a fourth lens arranged sequentially from the object plane to the image plane. The seventh surface of the third lens and the ninth surface of the fourth lens are both concave, and the eighth surface of the third lens and the tenth surface of the fourth lens are both convex. The eighth surface and the ninth surface are bonded together.

[0011] The eleventh surface of the plano-convex lens is a plane, and the twelfth surface is a convex surface.

[0012] Preferably, the radii of curvature of the first surface to the twelfth surface are 33.434 mm, 237.119 mm, 16.439 mm, -601.931 mm, -601.931 mm, 10.961 mm, -9.915 mm, -12.881 mm, -12.881 mm, -12.826 mm, infinite, and -87.809 mm, respectively.

[0013] Preferably, the air gaps between adjacent lenses in the main lens are as follows: 3.95 mm between the meniscus lens and the first lens, 7.42 mm between the second lens and the third lens, and 1.13 mm between the fourth lens and the plano-convex lens. The center thicknesses of each lens in the main lens are as follows: 8.314 mm for the meniscus lens, 4.719 mm for the first lens, 3.000 mm for the second lens, 3.002 mm for the third lens, 3.037 mm for the fourth lens, and 4.052 mm for the plano-convex lens.

[0014] A second objective of this invention is to provide an optical component for a 10x objective lens, comprising a main lens from the optical component of the 5x objective lens, and a secondary lens assembly consisting of a secondary lens and an aperture stop disposed between the main lens and the secondary lens.

[0015] Preferably, the aperture stop is an aperture stop with adjustable aperture.

[0016] Preferably, the secondary lens consists of two sets of lenses, which are a biconvex lens and a biconcave lens, respectively, from the object plane to the image plane.

[0017] Preferably, the radius of curvature of the thirteenth surface of the biconvex lens is 184.691 mm, the radius of curvature of the fourteenth surface is -185.191 mm, and the radius of curvature of the fifteenth surface of the biconcave lens is -53.022 mm and the radius of curvature of the sixteenth surface is 44.521 mm.

[0018] Preferably, the center thickness of the biconvex lens is 4.976 mm, the center thickness of the biconcave lens is 2.688 mm, the air gap between the biconvex lens and the biconcave lens is 63.684 mm, the air gap between the main lens and the aperture is 27.75 mm, and the air gap between the aperture and the secondary lens is 52.27 mm.

[0019] The third objective of this invention is to provide a long-distance, wide-field-of-view switchable microscope objective for measuring objects in liquids, using the optical components of the 10x objective lens. By switching the secondary lens assembly, microscopic observation at two magnifications—5x and 10x—can be achieved at an object distance greater than 75mm. The 5x objective lens has a magnification of 5x and is suitable for an object surface greater than 10mm × 10mm. When the secondary lens assembly is switched to be combined with the 5x objective lens, the magnification is 10x and it is suitable for an object surface greater than 6mm × 6mm.

[0020] Preferably, the long object distance and wide field of view switchable microscope objective for measuring objects in liquids has the following characteristics: when the 5x objective lens is used, the resolution in the entire field of view is higher than 1µm and the distortion is no greater than 0.06%; when the 10x objective lens is used, the resolution in the entire field of view is higher than 2µm and the distortion is no greater than 1.6%.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention improves the design of the optical lens of the microscope objective, enabling the use of the main lens alone or the addition of a secondary lens assembly without changing the optical length of the system, and achieves switching between 5x and 10x magnification, thus simplifying the operation when applied to microscopic observation.

[0023] The switchable microscope objective prepared by this invention has the advantages of long object distance and large field of view, enabling microscopic observation of objects in liquid environments. Especially in the environment of 632.8nm wavelength, it has good transmission characteristics, high resolution and small distortion across the entire field of view. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main lens in this invention;

[0025] Figure 2 for Figure 1 A cross-sectional view along the AA direction;

[0026] Figure 3 This is a diagram showing the focal points of the 5x lens in this invention across the entire field of view from -5mm to 5mm.

[0027] Figure 4 This is a diagram showing the field-of-view distortion of the 5x lens in this invention;

[0028] Figure 5 This is a schematic diagram of the structure of the main lens, aperture, and secondary lens in this invention;

[0029] Figure 6 for Figure 4 A cross-sectional view along the BB direction;

[0030] Figure 7This is a diagram showing the focal points of the 10x lens in this invention across the entire field of view from -3mm to 3mm.

[0031] Figure 8 This is a diagram showing the field-of-view distortion of the 10x lens in this invention;

[0032] Figure 9 The 5x lens in this invention ( Figure 9 (A) or 10x lens ( Figure 9 (B) Schematic diagram of the observation of the object under test.

[0033] In the diagram: 1. Main lens; 2. Secondary lens; L1. Meniscus lens; G10. First cemented doublet lens; G11. Second cemented doublet lens; L2. First lens; L3. Second lens; L4. Third lens; L5. Fourth lens; L6. Plano-convex lens; AS9. Aperture stop; L7. Biconvex lens; L8. Biconcave lens; 3. Cuvette; 4. Object to be tested. Detailed Implementation

[0034] 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 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be noted that, in this specific embodiment, the radius of curvature of the arc surface convex to the object surface in each lens is positive, the radius of curvature of the corresponding arc surface convex to the image surface is negative, and the radius of curvature of the plane is infinite.

[0036] This invention provides a technical solution: a long object distance, large field of view, and switchable magnification microscope objective for measuring objects in liquids, comprising: a main lens 1.

[0037] like Figure 1 and Figure 2 As shown, specifically, the main lens 1 consists of four groups of lenses, which are, from the object plane to the image plane, a meniscus lens L1, a first cemented doublet lens G10, a second cemented doublet lens G11, and a plano-convex lens L6.

[0038] In the meniscus lens L1, one side of the surface adjacent to the object plane (the first surface) is convex, and the other side (the second surface) is concave.

[0039] The first cemented doublet lens G10 is composed of a first lens L2 and a second lens L3 arranged sequentially from the object plane to the image plane. The first lens L2 has a convex surface on one side (the third surface) near the object plane and a convex surface on the other side (the fourth surface). The second lens L3 has a concave surface on one side (the fifth surface) near the object plane and a concave surface on the other side (the sixth surface), and the fourth and fifth surfaces are attached together.

[0040] The second cemented doublet lens G11 is composed of a third lens L4 and a fourth lens L5 arranged sequentially from the object plane to the image plane. The third lens L4 has a concave surface on one side (seventh surface) near the object plane and a convex surface on the other side (eighth surface). The fourth lens L5 has a concave surface on one side (ninth surface) near the object plane and a convex surface on the other side (tenth surface), and the eighth and ninth surfaces are bonded together.

[0041] The plano-convex lens L6 has a flat surface (eleventh surface) on one side of the object plane and a convex surface on the other side (twelfth surface).

[0042] Furthermore, the curvature radius, center thickness, and material of each lens in the main lens 1 and the secondary lens 2 are shown in Table 1.

[0043] The air gap between adjacent lenses in main lens 1 is:

[0044] The distance between the meniscus lens L1 and the first lens L2 is S2=3.95mm, the distance between the second lens L3 and the third lens L4 is S5=7.42mm, and the distance between the fourth lens L5 and the plano-convex lens L6 is S8=1.13mm.

[0045] The aforementioned main lens 1 is used as a 5x lens in a microscope as an objective lens. A 10mm×10mm dot array is set in the X and Y directions of the object plane, and the object plane point light source angle is set to 3° with an incident wavelength of 632.8nm.

[0046] Thus, the microscope using the aforementioned 5x lens is suitable for microscopic observation with an object plane larger than 10mm × 10mm, a magnification of 5x, and an object distance greater than 75mm.

[0047] The focal point array and field distortion of the aforementioned main lens 1 across the entire field of view from -5mm to 5mm were tested, and the results are as follows: Figure 3 and Figure 4 As shown, the overall length of the tested sample is 434.017 mm, the resolution of the main lens 1 in the entire field of view is higher than 1 μm, and the distortion is no greater than 0.06%.

[0048] The long object distance, large field of view, and switchable magnification microscope objective provided in this specific embodiment for measuring objects in liquids further includes a secondary lens assembly consisting of a secondary lens 2 and an aperture AS9.

[0049] like Figure 5 and Figure 6 As shown, specifically, the aperture stop AS9 is an aperture stop AS9 with adjustable aperture.

[0050] Specifically, the secondary lens 2 consists of two sets of lenses, namely a biconvex lens L7 and a biconcave lens L8, which are arranged from the object plane to the image plane. The surface of the biconvex lens L7 near the object plane is the thirteenth surface and the other side is the fourteenth surface. The surface of the biconcave lens L8 near the object plane is the fifteenth surface and the other side is the sixteenth surface.

[0051] Furthermore, the curvature radius, center thickness, and material of each lens in the secondary lens 2 are shown in Table 1.

[0052] The air gap between adjacent lenses in secondary lens 2 is:

[0053] The distance between the biconvex lens L7 and the biconcave lens L8 is S13 = 63.684 mm.

[0054] The aperture AS9 is located between the main lens 1 and the secondary lens 2. The air gap S10 between the main lens 1 and the aperture AS9 is 27.75mm, and the distance between the aperture AS9 and the secondary lens 2 is 52.27mm.

[0055] The aforementioned main lens 1, aperture AS9, and secondary lens 2 form a 10x lens, which is used in a microscope as an objective lens. A 6mm×6mm dot array is set in the X and Y directions of the object plane, and the object plane point light source angle is set to 2° with an incident wavelength of 632.8nm.

[0056] Thus, the microscope using the aforementioned 10x lens is suitable for microscopic observation with an object surface larger than 6mm × 6mm, a magnification of 10x, and an object distance greater than 75mm.

[0057] The focus point array and field distortion map of the aforementioned 10x lens in the full field of view from -3mm to 3mm were tested, and the results are as follows: Figure 7 and Figure 8 As shown, the resolution of the main lens 1 in the entire field of view is higher than 2µm, and the distortion is no greater than 1.6%.

[0058]

[0059] In summary, when the main lens 1 or the main lens 1 + secondary lens assembly is used as an objective lens in a microscope, it is possible to switch between 5x and 10x magnification by attaching and detaching the secondary lens assembly while maintaining a constant overall working distance. The overall optical length remains unchanged, and it can be used for microscopic observation at different magnifications without adjusting the object distance, while maintaining good characteristics.

[0060] Table 2 shows the characteristics of microscopes at different magnifications when the object distance is 77 mm. The distortion is no greater than 0.06% at 5x magnification and no greater than 1.2% at 10x magnification.

[0061]

[0062] It should be noted that, in the actual application of the above-mentioned main lens 1, considering the processing tolerance and assembly difficulty, the geometric dimensions of each lens decrease sequentially along the direction from the object plane to the image plane, which facilitates the coaxial processing of the lens barrel in the later stage to ensure the concentricity of the optical system. In order to ensure that the 5x objective lens has a field of view of 10mm×10mm, the diameter of the meniscus lens should not be less than 10mm.

[0063] It should be noted that when the 5x or 10x lens provided in this specific embodiment is used as an objective lens for microscopic observation under a microscope, such as... Figure 9 As shown, a cuvette 3 with a glass wall thickness of 2 mm is used to hold the liquid. The test part of the sample 4 is immersed in the liquid. The test part of the sample 4 is used as the object surface and is observed using a microscope.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An optical component for a 5x objective lens, characterized in that, include: The main lens (1) is composed of a meniscus lens (L1), a first cemented doublet lens (G10), a second cemented doublet lens (G11), and a plano lens (L6) from the object plane to the image plane. The first surface of the meniscus lens (L1) is convex, and the second surface is concave. The first cemented doublet lens (G10) is composed of a first lens (L2) and a second lens (L3) arranged sequentially from the object plane to the image plane. The third and fourth surfaces of the first lens (L2) are both convex, and the fifth and sixth surfaces of the second lens (L3) are both concave. The fourth surface and the fifth surface are bonded together. The second cemented doublet lens (G11) is composed of a third lens (L4) and a fourth lens (L5) arranged sequentially from the object plane to the image plane. The seventh surface of the third lens (L4) and the ninth surface of the fourth lens (L5) are both concave, and the eighth surface of the third lens (L4) and the tenth surface of the fourth lens (L5) are both convex. The eighth surface and the ninth surface are bonded together. The eleventh surface of the plano-convex lens (L6) is a plane, and the twelfth surface is a convex surface; The radii of curvature of the first to the twelfth surfaces are 33.434 mm, 237.119 mm, 16.439 mm, -601.931 mm, -601.931 mm, 10.961 mm, -9.915 mm, -12.881 mm, -12.881 mm, -12.826 mm, infinite, and -87.809 mm, respectively. The air gaps between adjacent lenses in the main lens (1) are as follows: 3.95 mm between the meniscus lens (L1) and the first lens (L2), 7.42 mm between the second lens (L3) and the third lens (L4), and 1.13 mm between the fourth lens (L5) and the plano-convex lens (L6). The center thicknesses of each lens in the main lens (1) are as follows: 8.314 mm for the meniscus lens (L1), 4.719 mm for the first lens (L2), 3.000 mm for the second lens (L3), 3.002 mm for the third lens (L4), 3.037 mm for the fourth lens (L5), and 4.052 mm for the plano-convex lens (L6). The material of the meniscus lens (L1) is H-LAK6A, the material of the first lens (L2) is H-ZK3, the material of the second lens (L3) is H-BAK5, the material of the third lens (L4) is H-ZF11, the material of the fourth lens (L5) is H-LAK59A, and the material of the plano-convex lens (L6) is H-LAK7A.

2. An optical component for a 10x objective lens, comprising the main lens (1) in the optical assembly of the 5x objective lens according to claim 1, characterized in that, Also includes: A secondary lens (2) assembly consisting of a secondary lens (2) and an aperture stop (AS9) disposed between the main lens (1) and the secondary lens (2); The aperture stop (AS9) is an aperture stop (AS9) with adjustable aperture. The secondary lens (2) consists of two sets of lenses, which are a biconvex lens (L7) and a biconcave lens (L8) from the object plane to the image plane. The radius of curvature of the thirteenth surface of the biconvex lens (L7) is 184.691 mm, the radius of curvature of the fourteenth surface is -185.191 mm, and the radius of curvature of the fifteenth surface of the biconcave lens (L8) is -53.022 mm and the radius of curvature of the sixteenth surface is 44.521 mm. The center thickness of the biconvex lens (L7) is 4.976 mm, the center thickness of the biconcave lens (L8) is 2.688 mm, the air gap between the biconvex lens (L7) and the biconcave lens (L8) is 63.684 mm, the air gap between the main lens (1) and the aperture (AS9) is 27.75 mm, and the air gap between the aperture (AS9) and the secondary lens (2) is 52.27 mm. The material of the biconvex lens (L7) is H-BK7, and the material of the biconcave lens (L8) is H-BK7.

3. A long-distance, large-field-of-view, switchable-magnification microscope objective for measuring objects in liquids, employing the optical components of the 10x objective lens as described in claim 2, characterized in that: By switching the sub-lens (2) assembly, microscopic observation at two magnifications of 5x and 10x can be achieved at an object distance greater than 75mm. The 5x objective lens has a magnification of 5x and is suitable for an object surface greater than 10mm×10mm. When the sub-lens (2) assembly is switched to be combined with the 5x objective lens, the magnification is 10x and is suitable for an object surface greater than 6mm×6mm.

4. The long object distance, large field of view, and switchable magnification microscope objective for measuring objects in liquids according to claim 3, characterized in that: The long object distance, wide field of view, and switchable magnification microscope objective for measuring objects in liquids has the following characteristics: when the 5x objective lens is used, the resolution in the entire field of view is higher than 1µm and the distortion is no greater than 0.06%; when the 10x objective lens is used, the resolution in the entire field of view is higher than 2µm and the distortion is no greater than 1.6%.

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