An internal focusing microscopic optical system

Abstract

The present invention discloses an internal focusing microscopic optical system, which is composed of an object surface, a first transmissive group with a positive optical power, a second transmissive group with a negative optical power, and an image surface, which are sequentially arranged from the object side to the image side. The first transmissive group is composed of a first double concave lens, a first double convex lens, a second double convex lens, a positive meniscus lens, a third double convex lens, and a second double concave lens, which are arranged in sequence from the object side to the image side. The second transmissive group is composed of a third double concave lens. It has the characteristics of high diffraction order resolution, a large numerical aperture (NA) of 0.3, a paraxial magnification (PMAG) of -8.9, a working wavelength of 630 nm, low distortion, etc. At the same time, it has the characteristics of internal focusing function and short conjugate distance.

Description

Technical Field

[0001] The present invention belongs to the technical field of microscopic optics, and particularly relates to an internally focused microscopic optical system. Background Art

[0002] Microscopic optical systems are widely used in fields such as scientific research, medical diagnosis, and industrial inspection. Especially during the observation and analysis of tiny objects, microscopes play a crucial role. With the progress of technology, people have higher and higher requirements for microscopic optical systems. Especially in terms of focal length adjustment, traditional microscope systems often struggle to meet the needs of modern scientific research and industrial applications.

[0003] Existing microscopic optical systems usually rely on mechanical focusing. Although mechanical focusing is relatively simple, its adjustment accuracy is low, and mechanical wear is prone to occur during frequent focusing, affecting the service life. Especially under high-precision and high-frequency focusing requirements, the performance is significantly insufficient.

[0004] In addition, most of the focusing methods of traditional microscopic optical systems require external mechanical drive, which makes the structure of the system relatively complex and limits the compactness and flexibility of the microscopic system. In some special application scenarios, such as high-resolution imaging and fast-scanning observation, the existing technology cannot effectively meet the requirements of fast and precise focusing.

[0005] Therefore, how to design an internally focused microscopic optical system that can simplify the system structure, improve the focusing speed and stability while ensuring high-precision focusing of the microscopic optical system has become a technical problem urgently to be solved in this field.

[0006] The present invention proposes an internally focused microscopic optical system, aiming to overcome the deficiencies in the existing technology through an innovative focusing method, so as to provide a more precise, stable and efficient focal length adjustment solution to meet the requirements of modern microscopes in high-precision and high-frequency focusing applications. Summary of the Invention

[0007] To overcome the above deficiencies, an internally focused microscopic optical system is proposed. It has characteristics such as high diffraction-level resolution, a large numerical aperture (NA) of 0.3, a paraxial magnification (PMAG) of -8.9, a working wavelength of 630 nm, low distortion, etc. At the same time, it has characteristics such as an internally focused function and a short conjugate distance.

[0008] To achieve the above object, the technical solution adopted by the present invention is: to provide an internally focusing microscopic optical system, which is composed of an object surface, a first transmissive group with a positive optical power, a second transmissive group with a negative optical power, and an image surface, which are arranged in sequence from the object side to the image side. The first transmissive group is composed of a first biconcave lens, a first biconvex lens, a second biconvex lens, a positive meniscus lens, a third biconvex lens, and a second biconcave lens, which are arranged in sequence from the object side to the image side. The second transmissive group is composed of a third biconcave lens.

[0009] According to an internally focusing microscopic optical system of the present invention, a further preferred technical solution is: the ratio range of the focal length of the first transmissive group to the focal length of the optical system is (2.5, 3.5); the ratio range of the focal length of the second transmissive group to the focal length of the optical system is (-2.1, -1.5).

[0010] According to an internally focusing microscopic optical system of the present invention, a further preferred technical solution is: the second transmissive group is a motion compensation component for internal focusing.

[0011] According to an internally focusing microscopic optical system of the present invention, a further preferred technical solution is: the materials of the first biconcave lens and the second biconcave lens are heavy flint glass, the material of the first biconvex lens is lanthanum flint glass, the materials of the second biconvex lens and the positive meniscus lens are lanthanum crown glass, the material of the third biconvex lens is crown glass, and the material of the third biconcave lens is barium crown glass.

[0012] According to an internally focusing microscopic optical system of the present invention, a further preferred technical solution is: the first biconcave lens and the first biconvex lens are cemented to form a first cemented doublet, and the third biconvex lens and the second biconcave lens are cemented to form a second cemented doublet.

[0013] Compared with the prior art, the technical solution of the present invention has the following advantages / beneficial effects:

[0014] 1. The optical system of the present invention has characteristics such as high diffraction-level resolution, a large numerical aperture (NA) of 0.3, a paraxial magnification (PMAG) of -8.9, a working wavelength of 630 nm, a short conjugate distance, and low distortion, meeting the requirements of modern microscopes in high-precision and high-frequency focusing applications.

[0015] 2. The second transmissive group is a motion compensation group for internal focusing, having an internal focusing motion compensation function, and can compensate for the image plane offset error caused by object distance error and system component error through the forward and backward movement of the second transmissive group.

[0016] 3. The optical system of the present invention is composed of an object surface, a first transmissive group, a second transmissive group, and an image surface. All 7 lenses are spherical lenses made of glass, with a relatively low manufacturing cost, which is conducive to cost reduction and promotion. Description of the Drawings

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the optical system structure of an internal focusing microscopic optical system of the present invention.

[0019] Figure 2 It is a curve graph of the modulation transfer function of an internal focusing microscopic optical system of the present invention.

[0020] Figure 3 It is a spot diagram of an internal focusing microscopic optical system of the present invention.

[0021] Figure 4 It is a curve graph of the optical path difference of an internal focusing microscopic optical system of the present invention.

[0022] Figure 5 It is a distortion diagram of an internal focusing microscopic optical system of the present invention.

[0023] The marks in the figure are respectively: 1. First biconcave lens, 2. First biconvex lens, 3. Second biconvex lens, 4. Positive meniscus lens, 5. Third biconvex lens, 6. Second biconcave lens, 7. Third biconcave lens, 8. Object surface, 9. Image surface, G1. First transmission group, G2. Second transmission group. Specific Embodiments

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it may not be further defined and explained in subsequent drawings.

[0026] Example 1:

[0027] As Figure 1As shown in the figure, an internally focusing micro-optical system is provided. It consists of an object surface 8, a first transmissive group G1 with a positive optical power, a second transmissive group G2 with a negative optical power, and an image surface 9, which are arranged in sequence from the object side to the image side. The first transmissive group G1 has a positive optical power and is composed of a total of 6 lenses. From the object side to the image side, they are: a first biconcave lens 1 made of heavy flint glass, a first biconvex lens 2 made of lanthanum flint glass, a second biconvex lens 3 made of lanthanum crown glass, a positive meniscus lens 4 made of lanthanum crown glass, a third biconvex lens 5 made of crown glass, and a second biconcave lens 6 made of heavy flint glass. Of course, using different glasses to manufacture the lenses is only a relatively excellent solution. When necessary, other materials can also be used for manufacturing, as long as the usage requirements are met. The first biconcave lens 1 and the first biconvex lens 2 are cemented to form a first cemented lens, and the third biconvex lens 5 and the second biconcave lens 6 are cemented to form a second cemented lens. The cemented lens is a way of combining two lenses, which is only a combination means here, and other similar reasonable means can be adopted. The first transmissive group G1 mainly corrects aberrations such as spherical aberration, coma, sine aberration, field curvature, and distortion of the system, and corrects chromatic aberration through doublet cementing.

[0028] The first transmissive group G2 has a negative optical power and is composed of 1 lens, which is a third biconcave lens 7 made of barium crown glass. The first transmissive group G2 is a motion compensation component for internal focusing, and compensates for the image surface 9 offset error caused by object distance error and system part error through the forward and backward movement of the first transmissive group G2.

[0029] The ratio range of the focal length of the first transmissive group G1 to the focal length of the optical system is (2.5, 3.5); the ratio range of the focal length of the first transmissive group G2 to the focal length of the optical system is (-2.1, -1.5).

[0030] Embodiment 2:

[0031] Based on Embodiment 1, this embodiment gives an example of an internally focusing micro-optical system. The physical parameters of each lens in this embodiment meet the data requirements shown in Table 1:

[0032] Table 1 Physical parameters of each lens in this embodiment

[0033]

[0034] The internal focusing microscopic optical system of this embodiment has a working wavelength of 630±20nm, an object distance of 14mm, an object height of 0.28mm, and a numerical aperture (NA) of 0.3. The light rays emitted from the object plane pass through the first transmission group G1 and the second transmission group G2 in sequence and then form an image on the image plane 9 with an image height of 2.5mm. It has the characteristics of high diffraction order resolution, paraxial magnification (PMAG) of -8.9, low distortion (about 1.0%), short conjugate distance (66.2mm), internal focusing function, etc.

[0035] Figure 2 The modulation transfer function (MTF) curve of the internal focusing microscopic optical system of this embodiment is given. In the figure, the vertical coordinate OTF coefficient is the modulation transfer function of the fast Fourier transform, and the horizontal coordinate is the spatial frequency: line pairs per millimeter. It can be seen from the figure that the modulation transfer function (MTF) of the internal focusing microscopic optical system is close to the diffraction limit.

[0036] Figure 3 The spot diagrams of the internal focusing microscopic optical system of this embodiment are given. The unit of the legend in the figure is μm. It can be seen from the figure that the RMS spot radius of the internal focusing microscopic optical system in each field of view is less than 2μm.

[0037] Figure 4 The optical path difference curve of the internal focusing microscopic optical system of this embodiment is given. In the figure, ex: the x component of the ray aberration, ey: the y component of the ray aberration, px: the x entrance pupil coordinate, py: the y entrance pupil coordinate. It can be seen from the figure that the optical path difference of the internal focusing microscopic optical system is less than 0.2 wavelengths.

[0038] Figure 5 The distortion of the internal focusing microscopic optical system of this embodiment is given. It can be seen from the figure that the optical distortion of the optical system is about 1.0%.

[0039] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0040] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the protection scope of the present invention should be defined by the scope defined in the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and modifications can also be made, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. An internal focusing microscope optical system, characterized in that: The device is composed of an object plane, a first transmission group with positive optical focal length, a second transmission group with negative optical focal length, and an image plane, which are arranged in sequence from the object side to the image side. The first transmission group is composed of a first biconcave lens, a first biconvex lens, a second biconvex lens, a positive meniscus lens, a third biconvex lens, and a second biconcave lens, which are arranged in sequence from the object side to the image side. The second transmission group is composed of a third biconcave lens. The second transmission group is an internal focusing motion compensation component.

2. The internal focusing microscope optical system according to claim 1, characterized in that: The ratio of the focal length of the first transmission group to the focal length of the optical system is in the range of (2.5, 3.5); the ratio of the focal length of the second transmission group to the focal length of the optical system is in the range of (-2.1, -1.5).

3. The internal focusing microscope optical system according to claim 1, characterized in that: The first biconcave lens and the second biconcave lens are made of heavy flint glass, the first biconvex lens is made of lanthanum flint glass, the second biconvex lens and the positive meniscus lens are made of lanthanum crown glass, the third biconvex lens is made of crown glass, and the third biconcave lens is made of barium crown glass.

4. The internal focusing microscope optical system according to claim 1, characterized in that: The first biconcave lens and the first biconvex lens are glued together to form a first double glued lens, and the third biconvex lens and the second biconcave lens are glued together to form a second double glued lens.

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