A visible light ultra-large field of view optical structure

Abstract

The present invention belongs to the technical field of optical engineering, and particularly relates to a visible light ultra-large field-of-view optical structure, which sequentially includes a first lens with a negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a positive optical power, an aperture stop, a fifth lens with a positive optical power, a sixth lens with a positive optical power, a seventh lens with a negative optical power, and an image plane from the object side to the image side; each lens is a spherical lens and the centers of both sides of the spherical surface coincide with the optical axis of the system. Five kinds of lens materials are used, and the alignment tolerance between the lenses is relatively loose. The optical materials are simple to prepare and achieve excellent imaging quality. An optical field of 150° can be achieved, and the third-order aberration correction in the visible spectral range is realized. It not only simplifies the preparation process of the optical system, but also reduces the production cost. In addition, the optical structure of the present invention also has the characteristics of compact structure, simple integration, and excellent image quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical engineering, and particularly relates to a visible light ultra-wide field optical structure. Background Art

[0002] As an important tool for astronomical research, the telescope can not only deeply explore the mysteries of the universe, but also has a wide range of application fields. Among them, the telescope has unique advantages and potential in environmental monitoring, including agricultural production, photovoltaic industry, aerospace, astronomical observation, etc. Through the observation, remote sensing and data analysis of the telescope, the changes in the environment can be understood, promoting sustainable development and ecological protection.

[0003] In order to further improve environmental monitoring technology, it is of important application value and broad application prospects to research and develop high-quality sky imaging devices for fields such as agricultural production, photovoltaic industry, aerospace, and astronomical observation. Currently, in order to meet the requirement of system miniaturization for the developed visible light ultra-wide field optical system, when the optical field exceeds 140°, a high-order aspherical lens is added to the optical system for aberration balance. Although the application of the aspherical lens can effectively optimize the imaging quality of the optical system and increase the design freedom, the processing and alignment tolerances of its aspherical lens are relatively strict, and the detection difficulty is relatively high, which not only increases the manufacturing difficulty of the optical system, but also raises the manufacturing cost and time cost. Summary of the Invention

[0004] In view of this, the present invention aims to provide a visible light ultra-wide field optical structure to solve the problems of strict alignment tolerances, high detection difficulty, increased manufacturing cost and time cost caused by using aspherical lenses when the optical field exceeds 140°.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] [[ID=2,2]]A visible light ultra-wide field optical structure successively includes a first lens with a negative optical power, a second lens with a negative optical power, a third lens with a positive optical power, a fourth lens with a positive optical power, an aperture stop, a fifth lens with a positive optical power, a sixth lens with a positive optical power, a seventh lens with a negative optical power, and an image plane from the object side to the image side; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all spherical lenses, and the centers of both sides of each lens coincide with the optical axis of the visible light ultra-wide field optical structure;

[0007] The first lens and the second lens are made of a first optical material, the third lens and the seventh lens are made of a second optical material, the fourth lens is made of a third optical material, the fifth lens is made of a fourth optical material, and the sixth lens is made of a fifth optical material;

[0008] The refractive index ranges and Abbe number ranges of the first optical material, the second optical material, the third optical material, the fourth optical material, and the fifth optical material are all different.

[0009] Furthermore, the refractive index Nd of the first optical material satisfies: 1.8 ≤ Nd ≤ 1.82, and the Abbe number Vd of the first optical material satisfies: 46 ≤ Vd ≤ 48.

[0010] Furthermore, the refractive index Nd of the second optical material satisfies: 1.90 ≤ Nd ≤ 1.92, and the Abbe number Vd of the second optical material satisfies: 18.5 ≤ Vd ≤ 19.

[0011] Furthermore, the refractive index Nd of the third optical material satisfies: 1.49 ≤ Nd ≤ 1.52, and the Abbe number Vd of the third optical material satisfies: 80 ≤ Vd ≤ 82.

[0012] Furthermore, the refractive index Nd of the fourth optical material satisfies: 1.64 ≤ Nd ≤ 1.68, and the Abbe number Vd of the fourth optical material satisfies: 58 ≤ Vd ≤ 59.

[0013] Furthermore, the refractive index Nd of the fifth optical material satisfies: 1.57 ≤ Nd ≤ 1.59, and the Abbe number Vd of the fifth optical material satisfies: 61 ≤ Vd ≤ 62.

[0014] Furthermore, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

[0015] The object side surface of the second lens is a flat surface, and the image side surface of the second lens is a concave surface;

[0016] The object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

[0017] The object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a convex surface;

[0018] The object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface;

[0019] The object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface;

[0020] The object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a concave surface.

[0021] Further, the focal length range of the first lens is: -20 mm to -25 mm; the focal length range of the second lens is: -4 mm to -5 mm; the focal length range of the third lens is: 14 mm to 15 mm; the focal length range of the fourth lens is: 17 mm to 18 mm; the focal length range of the fifth lens is 10 mm to 11 mm; the focal length range of the sixth lens is 4 mm to 5 mm; the focal length range of the seventh lens is -6 mm to -7 mm.

[0022] Further, the thickness of the first lens is 0.8 mm to 1 mm, and the distance between the first lens and the second lens is 7 mm to 7.5 mm;

[0023] The thickness of the second lens is 0.8 mm to 1 mm, and the distance between the second lens and the third lens is 2.6 mm to 2.7 mm;

[0024] The thickness of the third lens is 3 mm to 3.5 mm, and the distance between the third lens and the fourth lens is 5 mm to 6 mm;

[0025] The thickness of the fourth lens is 0.8 mm to 1 mm, and the distance between the fourth lens and the fifth lens is 1.8 mm to 2 mm;

[0026] The thickness of the fifth lens is 0.8 mm to 1 mm, and the distance between the fifth lens and the sixth lens is 0.1 mm to 0.3 mm;

[0027] The thickness of the sixth lens is 1.3 mm to 1.5 mm, and the distance between the sixth lens and the seventh lens is 0.1 mm to 0.3 mm;

[0028] The thickness of the seventh lens is 1.5 mm to 1.7 mm, and the distance between the seventh lens and the image plane is 3 mm to 3.3 mm.

[0029] Further, the aperture number F of the visible light ultra-wide field optical structure is 1.6 to 1.9, and the working wavelength range is 480 nm to 670 nm.

[0030] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0031] A visible light ultra-wide field optical structure according to the present invention adopts a global spherical lens combination method for the design of the optical structure. Five types of lens materials are used, with a total of seven spherical lenses. The alignment tolerance between the lenses is relatively loose, the optical material preparation is simple, and excellent imaging quality is achieved. An optical field of 150° can be realized, and the third-order aberration correction in the visible spectral band is achieved. This not only simplifies the preparation process of the optical system but also reduces the production cost. In addition, the optical structure of the present invention also has the characteristics of compact structure, easy integration, and excellent image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 FIG. is a schematic diagram of a visible light ultra-wide field optical structure according to an embodiment of the present invention;

[0034] Figure 2 FIG. is a light path diagram of a visible light ultra-wide field optical structure according to an embodiment of the present invention;

[0035] Figure 3 FIG. is a spot diagram of each field of a visible light ultra-wide field optical structure according to an embodiment of the present invention.

[0036] DESCRIPTION OF THE REFERENCE NUMERALS:

[0037] 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, aperture stop; 6, fifth lens; 7, sixth lens; 8, seventh lens; 9, image plane. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar components in different embodiments adopt related similar component numbers. In the following embodiments, many details are described to enable a better understanding of the present invention. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the present invention are not shown or described in the specification, in order to avoid the core part of the present invention being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the field.

[0039] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various embodiments. At the same time, the steps or actions in the method description can also be adjusted in the order that is obvious to those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0040] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "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 accompanying 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 component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "plurality" is two or more.

[0041] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0043] As Figures 1 to 3 shown, a visible light ultra-large field of view optical structure successively includes a first lens 1 with a negative focal power, a second lens 2 with a negative focal power, a third lens 3 with a positive focal power, a fourth lens 4 with a positive focal power, a fifth lens 6 with a positive focal power, a sixth lens 7 with a positive focal power, a seventh lens 8 with a negative focal power, and an image plane 9 from the object side to the image side. An aperture stop 5 is located between the fourth lens 4 and the fifth lens 6, and the aperture range of the aperture stop 5 is 3 mm to 4 mm.

[0044] Specifically, the visible light ultra-large field of view optical structure uses 7 spherical lenses to balance the aberration of an infinitely distant target beam. At the point on the optical axis of the optical structure, the aberration is small, but at the point outside the optical axis, especially at the edge of the field of view, a large aberration is generated, and the aberration is corrected by 7 spherical lenses. The infinitely distant target light rays reach the image plane after passing through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 6, the sixth lens 7, and the seventh lens 8. Among them, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 6, the sixth lens 7, and the seventh lens 8 are lenses with focal power, and the connecting lines of the centers of all the lenses coincide with the optical axis of the visible light ultra-large field of view optical structure.

[0045] Specifically, the f-number F of the visible light ultra-large field of view optical structure is 1.6 to 1.9, and the working wavelength range is 480 nm to 670 nm.

[0046] Specifically, the lens materials are five different grades of optical materials. Among them, the first lens 1 and the second lens 2 are made of the first optical material, the third lens 3 and the seventh lens 8 are made of the second optical material, the fourth lens 4 is made of the third optical material, the fifth lens 6 is made of the fourth optical material, and the sixth lens 7 is made of the fifth optical material;

[0047] The refractive index ranges and Abbe number ranges of the first optical material, the second optical material, the third optical material, the fourth optical material, and the fifth optical material are all different.

[0048] Specifically, the imaging is corrected by optical materials with five different refractive indices and Abbe numbers of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 6, the sixth lens 7, and the seventh lens 8, so as to obtain a large field of view and high-quality imaging. The refractive index Nd of the first optical material satisfies: 1.8 ≤ Nd ≤ 1.82, and the Abbe number Vd of the first optical material satisfies: 46 ≤ Vd ≤ 48; the refractive index Nd of the second optical material and the sixth optical material satisfies: 1.90 ≤ Nd ≤ 1.92, and the Abbe number Vd of the second optical material and the sixth optical material satisfies: 18.5 ≤ Vd ≤ 19; the refractive index Nd of the third optical material satisfies: 1.49 ≤ Nd ≤ 1.52, and the Abbe number Vd of the third optical material satisfies: 80 ≤ Vd ≤ 82; the refractive index Nd of the fourth optical material satisfies: 1.64 ≤ Nd ≤ 1.68, and the Abbe number Vd of the fourth optical material satisfies: 58 ≤ Vd ≤ 59; the refractive index Nd of the fifth optical material satisfies: 1.57 ≤ Nd ≤ 1.59, and the Abbe number Vd of the fifth optical material satisfies: 61 ≤ Vd ≤ 62.

[0049] It should be noted that the present application does not specifically limit the compositions of the first optical material, the second optical material, the third optical material, the fourth optical material, and the fifth optical material. It is only required that the five materials respectively satisfy the corresponding refractive index ranges and Abbe number ranges.

[0050] Specifically, the object side surface of the first lens 1 is a convex surface, and the image side surface of the first lens 1 is a concave surface; the object side surface of the second lens 2 is a flat surface, and the image side surface of the second lens 2 is a concave surface; the object side surface of the third lens 3 is a convex surface, and the image side surface of the third lens 3 is a convex surface; the object side surface of the fourth lens 4 is a convex surface, and the image side surface of the fourth lens 4 is a convex surface; the object side surface of the fifth lens 6 is a convex surface, and the image side surface of the fifth lens 6 is a convex surface; the object side surface of the sixth lens 7 is a convex surface, and the image side surface of the sixth lens 7 is a convex surface; the object side surface of the seventh lens 8 is a concave surface, and the image side surface of the seventh lens 8 is a concave surface.

[0051] Specifically, through the optimized design of different optical material combinations, the curvature radii of both sides of the lens, and the lens thickness, the focal lengths of each lens are obtained. The focal length range of the first lens 1 is: -20 mm to -25 mm; the focal length range of the second lens 2 is: -4 mm to -5 mm; the focal length range of the third lens 3 is: 14 mm to 15 mm; the focal length range of the fourth lens 4 is: 17 mm to 18 mm; the focal length range of the fifth lens 6 is 10 mm to 11 mm; the focal length range of the sixth lens 7 is 4 mm to 5 mm; the focal length range of the seventh lens 8 is -6 mm to -7 mm.

[0052] Specifically, the thickness of the first lens 1 is 0.8 mm to 1 mm, and the distance between the first lens 1 and the second lens 2 is 7 mm to 7.5 mm; the thickness of the second lens 2 is 0.8 mm to 1 mm, and the distance between the second lens 2 and the third lens 3 is 2.6 mm to 2.7 mm; the thickness of the third lens 3 is 3 mm to 3.5 mm, and the distance between the third lens 3 and the fourth lens 4 is 5 mm to 6 mm; the thickness of the fourth lens 4 is 0.8 mm to 1 mm, and the distance between the fourth lens 4 and the fifth lens 6 is 1.8 mm to 2 mm; the thickness of the fifth lens 6 is 0.8 mm to 1 mm, and the distance between the fifth lens 6 and the sixth lens 7 is 0.1 mm to 0.3 mm; the thickness of the sixth lens 7 is 1.3 mm to 1.5 mm, and the distance between the sixth lens 7 and the seventh lens 8 is 0.1 mm to 0.3 mm; the thickness of the seventh lens 8 is 1.5 mm to 1.7 mm, and the distance between the seventh lens 8 and the image plane 9 is 3 mm to 3.3 mm.

[0053] Further, taking the specific parameters of each lens in Table 1 as an example, where the unit of the radius of curvature is mm; the unit of the lens thickness is mm; the unit of the interval is mm.

[0054] Table 1

[0055]

[0056] An optical structure with a super-large visible light field of view according to the present invention adopts a combination of all-spherical lenses to design the optical structure. Five types of lens materials are used, with a total of seven spherical lenses. The first lens 1 collects the far-field beam energy within a 150° field of view, and the subsequent six spherical lenses are reasonably combined for aberration correction. Since the optical structure has a relatively large field of view and a relatively wide working wavelength band, a combination of lenses made of optical materials with specific refractive indices and dispersion coefficients is used to correct the off-axis aberration and chromatic aberration of the optical structure. The alignment tolerance between the lenses is relatively loose, the preparation of the optical materials is simple, and excellent imaging quality is achieved. An optical field of view of 150° can be realized, and the third-order aberration correction in the visible spectral band can be achieved. It not only simplifies the preparation process of the optical system, but also reduces the production cost. In addition, the optical structure with a super-large visible light field of view of the present invention also has the characteristics of a compact structure, simple integration, and excellent image quality.

[0057] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present invention can be achieved, and no limitations are imposed herein.

[0058] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A visible light ultra-large field of view optical structure, characterized by: The visible light ultra-wide field of view optical structure includes, from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, an aperture, a fifth lens with positive optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, and an image plane; the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all spherical lenses, and the centers of both spheres coincide with the optical axis of the visible light ultra-wide field of view optical structure; The first lens and the second lens are made of a first optical material, the third lens and the seventh lens are made of a second optical material, the fourth lens is made of a third optical material, the fifth lens is made of a fourth optical material, and the sixth lens is made of a fifth optical material; The refractive index ranges and Abbe number ranges of the first optical material, the second optical material, the third optical material, the fourth optical material and the fifth optical material are all different; The focal length range of the first lens is: -20mm~-25mm; the focal length range of the second lens is: -4mm~-5mm; the focal length range of the third lens is: 14mm~15mm; the focal length range of the fourth lens is: 17mm~18mm; the focal length range of the fifth lens is: 10mm~11mm; the focal length range of the sixth lens is: 4mm~5mm; the focal length range of the seventh lens is: -6mm~-7mm.

2. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The refractive index Nd of the first optical material satisfies: 1.8≤Nd≤1.82, and the Abbe number Vd of the first optical material satisfies: 46≤Vd≤48.

3. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The refractive index Nd of the second optical material satisfies: 1.90≤Nd≤1.92, and the Abbe number Vd of the second optical material satisfies: 18.5≤Vd≤19.

4. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The refractive index Nd of the third optical material satisfies: 1.49≤Nd≤1.52, and the Abbe number Vd of the third optical material satisfies: 80≤Vd≤82.

5. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The refractive index Nd of the fourth optical material satisfies: 1.64≤Nd≤1.68, and the Abbe number Vd of the fourth optical material satisfies: 58≤Vd≤59.

6. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The refractive index Nd of the fifth optical material satisfies: 1.57≤Nd≤1.59, and the Abbe number Vd of the fifth optical material satisfies: 61≤Vd≤62.

7. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The object-side surface of the first lens is an outer convex surface, and the image-side surface of the first lens is an inner concave surface; The object-side surface of the second lens is a flat surface, and the image-side surface of the second lens is an inner concave surface; The object-side surface of the third lens is an outward convex surface, and the image-side surface of the third lens is an outward convex surface; The object-side surface of the fourth lens is an outward convex surface, and the image-side surface of the fourth lens is an outward convex surface; The object-side surface of the fifth lens is an outward convex surface, and the image-side surface of the fifth lens is an outward convex surface; The object-side surface of the sixth lens is an outward convex surface, and the image-side surface of the sixth lens is an outward convex surface; The object-side surface of the seventh lens is an inner concave surface, and the image-side surface of the seventh lens is an inner concave surface.

8. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The thickness of the first lens is 0.8 mm to 1 mm, and the distance between the first lens and the second lens is 7 mm to 7.5 mm; The thickness of the second lens is 0.8 mm to 1 mm, and the distance between the second lens and the third lens is 2.6 mm to 2.7 mm; The thickness of the third lens is 3 mm to 3.5 mm, and the distance between the third lens and the fourth lens is 5 mm to 6 mm; The thickness of the fourth lens is 0.8 mm to 1 mm, and the distance between the fourth lens and the fifth lens is 1.8 mm to 2 mm; The thickness of the fifth lens is 0.8 mm to 1 mm, and the distance between the fifth lens and the sixth lens is 0.1 mm to 0.3 mm; The thickness of the sixth lens is 1.3 mm to 1.5 mm, and the distance between the sixth lens and the seventh lens is 0.1 mm to 0.3 mm; The thickness of the seventh lens is 1.5 mm to 1.7 mm, and the distance between the seventh lens and the image plane is 3 mm to 3.3 mm.

9. The visible light ultra-large field of view optical structure according to claim 1, characterized in that: The aperture number F of the visible light ultra-large field of view optical structure is 1.6-1.9, and the operating band is 480nm-670nm.

Images