Wide-angle large-aperture lens

Abstract

The invention provides a wide-angle large-aperture lens. The wide-angle large-aperture lens is sequentially composed of a diaphragm, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and plate glass from an object side surface to an image surface, conditional expressions are satisfied: Td / ENPD < = 2.5, and 1.0 < = TTL / Tp < = 2.0. Through reasonable focal power matching, high imaging quality of the lens is guaranteed, the total length of the lens is effectively shortened, the lens meets the requirement for miniaturization, the lens has the characteristic of large aperture due to reasonable parameter matching of the lenses, and the shooting requirement of people in a weak light environment is met.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and particularly to a wide-angle large-aperture lens. Background Art

[0002] With the continuous development of science and technology, the field of photography has been continuously expanded. When people engage in outdoor activities such as cycling, driving, and traveling, it has become increasingly popular to record their good times through photography and share them on social media. Currently, the sports camera devices used for photographing and recording work and life in the market are becoming more and more diverse, and people's needs are also becoming more diverse. To obtain better imaging quality and night scene effects, more lens elements are often required, and the volume is relatively large, which cannot meet the requirements of lens miniaturization. For example, Chinese Patent Application Publication No. CN113156626A, with a publication date of July 23, 2021, discloses an eight-element large-aperture high-pixel imaging lens, which sequentially includes, from the object side to the image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; the eight-element large-aperture high-pixel imaging lens satisfies the following relationship: ImgH / Fno>3.55; where ImgH is half of the length of the diagonal of the effective imaging area of the eight-element large-aperture high-pixel imaging lens, and Fno is the aperture number of the eight-element large-aperture high-pixel imaging lens. Due to users' high requirements for imaging resolution, therefore, how to continuously improve imaging resolution and field of view while maintaining a compact volume has become an urgent technical problem to be solved. In view of this situation, it is urgently needed to be improved. Summary of the Invention

[0003] Aiming at the above problems, the present invention provides a wide-angle large-aperture lens, which adopts an eight-element lens combination. Through reasonable power distribution, while ensuring high imaging quality of the lens, the overall length of the lens is effectively shortened, so that the lens meets the requirements of miniaturization. The reasonable parameter combination between the lenses makes the lens have the characteristics of a large aperture and meets people's shooting needs in low-light environments.

[0004] To achieve the above object, the present invention is solved by the following technical solutions:

[0005] A wide-angle large-aperture lens is composed of a diaphragm, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a flat glass in sequence from the object side to the image side;

[0006] The first lens is configured as a convex-concave lens with a positive optical power, the second lens is configured as a convex-concave meniscus lens with a negative optical power, the third lens is configured as having a positive optical power, the fourth lens is configured as having a negative optical power, the fifth lens is configured as having a negative optical power, the sixth lens is configured as a convex-concave lens with a positive optical power, the seventh lens is configured as having a negative optical power, and the eighth lens is configured as having a negative optical power;

[0007] It satisfies the conditional formula:

[0008] Td / ENPD ≤ 2.5, where Td is the distance on the optical axis from the object side surface of the first lens to the image side surface of the eighth lens, and ENPD is the entrance pupil diameter of the wide-angle large aperture lens;

[0009] 1.0 ≤ TTL / Tp ≤ 2.0, where TTL is the overall optical length of the wide-angle large aperture lens, and Tp is the sum of the thicknesses of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens on the optical axis.

[0010] Preferably, it satisfies the conditional formula 0 ≤ TTL / OD ≤ 1.0, where OD is the maximum aperture of the lens.

[0011] Preferably, it satisfies the conditional formula f1 / f ≥ 2.0, where f1 is the focal length of the first lens, and f is the focal length of the wide-angle large aperture lens.

[0012] Preferably, it satisfies the conditional formula f6 / f ≤ 1.0, where f6 is the focal length of the sixth lens, and f is the focal length of the wide-angle large aperture lens.

[0013] Preferably, it satisfies the conditional formula 0 ≤ SAG62 / CT6 ≤ 1.0, where SAG62 is the distance on the optical axis from the intersection point of the image side surface of the sixth lens and the optical axis to the effective semi-aperture vertex of the image side surface of the eighth lens, and CT6 is the maximum thickness of the sixth lens on the optical axis.

[0014] Preferably, it satisfies the conditional formula 0.5 ≤ Y14 / Y15 ≤ 1.5, where Y14 is the perpendicular distance from the critical point on the object side surface of the seventh lens to the optical axis, and Y15 is the perpendicular distance from the critical point on the image side surface of the seventh lens to the optical axis.

[0015] Preferably, it satisfies the conditional formula Y16 / Y17 ≤ 3, where Y16 is the perpendicular distance from the critical point on the object side surface of the eighth lens to the optical axis, and Y17 is the perpendicular distance from the critical point on the image side surface of the eighth lens to the optical axis.

[0016] The beneficial effects of the present invention are:

[0017] 1. Meeting the conditional expression Td / ENPD ≤ 2.5 can improve the light input of a wide-angle large-aperture lens, endow the lens with the characteristics of a large aperture, and at the same time can effectively control the volume of the lens to ensure the miniaturization of the lens.

[0018] 2. Meeting the conditional expression 1.0 ≤ TTL / Tp ≤ 2.0 can maintain the structural compactness of a wide-angle large-aperture lens, effectively reduce the volume of the wide-angle large-aperture lens, and at the same time can effectively reduce the complexity of lens assembly, further improving the imaging quality of the lens.

[0019] 3. Meeting the conditional expression 0 ≤ TTL / OD ≤ 1.0 can ensure that the lens has a small overall optical length and aperture, thereby ensuring the miniaturization of the lens.

[0020] 4. Meeting the conditional expression f1 / f ≥ 2.0 can avoid too large a focal power of the first lens and reduce the sensitivity of the first lens.

[0021] 5. Meeting the conditional expression f6 / f ≤ 1.0 can effectively shorten the lens length to ensure the miniaturization of the lens.

[0022] 6. Meeting the conditional expression 0 ≤ SAG62 / CT6 ≤ 1.0 can ensure that the sixth lens does not bend excessively, which is beneficial to the molding and manufacturing of the sixth lens, and further more beneficial to reducing the overall optical length of the wide-angle large-aperture lens.

[0023] 7. Meeting the conditional expression 0.5 ≤ Y14 / Y15 ≤ 1.5 can improve the aberration correction ability of the seventh lens and effectively improve the imaging resolution of the wide-angle large-aperture lens.

[0024] 8. Meeting the conditional expression Y16 / Y17 ≤ 3 can improve the aberration correction ability of the eighth lens and effectively improve the imaging resolution of the wide-angle large-aperture lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic cross-sectional structure diagram of the first embodiment of the present invention;

[0026] Figure 2 It is a curve graph of the optical transfer function of the first embodiment of the present invention;

[0027] Figure 3 It is a spot diagram of the first embodiment of the present invention;

[0028] Figure 4 It is a schematic cross-sectional structure diagram of the second embodiment of the present invention;

[0029] Figure 5 It is a curve graph of the optical transfer function of the second embodiment of the present invention;

[0030] Figure 6 Spot diagram of the second embodiment of the present invention;

[0031] Figure 7 Schematic cross-sectional structure diagram of the third embodiment of the present invention;

[0032] Figure 8 Optical transfer function curve diagram of the third embodiment of the present invention;

[0033] Figure 9 Spot diagram of the third embodiment of the present invention.

[0034] Reference numerals in the drawings are: image plane 20, aperture 10, first lens 11, second lens 12, third lens 13, fourth lens 14, fifth lens 15, sixth lens 16, seventh lens 17, eighth lens 18, flat glass 19. Detailed implementation manners

[0035] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0037] In this embodiment, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object to be photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0038] The present invention provides a wide-angle large-aperture lens, which is sequentially composed of a diaphragm 10, a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, a sixth lens 16, a seventh lens 17, an eighth lens 18, and a flat glass 19 from the object side to the image plane 20; the first lens 11 is set as a convex-concave lens with a positive optical power, the second lens 12 is set as a convex-concave meniscus lens with a negative optical power, the third lens 13 is set as having a positive optical power, the fourth lens 14 is set as having a negative optical power, the fifth lens 15 is set as having a negative optical power, the sixth lens 16 is set as a convex-concave lens with a positive optical power, the seventh lens 17 is set as having a negative optical power, and the eighth lens 18 is set as having a negative optical power;

[0039] It satisfies the conditional formula:

[0040] Td / ENPD ≤ 2.5, where Td is the distance from the object side of the first lens 11 to the image side of the eighth lens 18 on the optical axis, and ENPD is the lens entrance pupil diameter of the wide-angle large-aperture lens; it can improve the light input of the wide-angle large-aperture lens, make the lens have the characteristics of a large aperture, and at the same time can effectively control the volume of the lens to ensure the miniaturization of the lens.

[0041] 1.0 ≤ TTL / Tp ≤ 2.0, where TTL is the overall optical length of the wide-angle large-aperture lens, and Tp is the total thickness of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, and the eighth lens 18 on the optical axis. It can maintain the structural compactness of the wide-angle large-aperture lens, effectively reduce the volume of the wide-angle large-aperture lens, and at the same time can effectively reduce the complexity of lens assembly and further improve the imaging quality of the lens.

[0042] Preferably, it satisfies the conditional formula 0 ≤ TTL / OD ≤ 1.0, where OD is the maximum aperture of the lens, which can ensure that the lens has a smaller overall optical length and aperture, and thus ensure the miniaturization of the lens.

[0043] Preferably, it satisfies the conditional formula f1 / f ≥ 2.0, where f1 is the focal length of the first lens 11 and f is the focal length of the wide-angle large-aperture lens, which can avoid too large optical power of the first lens and reduce the sensitivity of the first lens.

[0044] Preferably, it satisfies the conditional formula f6 / f ≤ 1.0, where f6 is the focal length of the sixth lens 16 and f is the focal length of the wide-angle large-aperture lens, which can effectively shorten the lens length to ensure the miniaturization of the lens.

[0045] Preferably, it satisfies the conditional expression 0 ≤ SAG62 / CT6 ≤ 1.0, where SAG62 is the distance on the optical axis from the intersection point of the image-side surface of the sixth lens 16 and the optical axis to the vertex of the effective semi-aperture of the image-side surface of the eighth lens 18, and CT6 is the maximum thickness of the sixth lens 16 on the optical axis. This can ensure that the sixth lens does not bend excessively, which is beneficial to the molding and manufacturing of the sixth lens, and further more beneficial to reducing the overall optical length of the wide-angle large-aperture lens.

[0046] Preferably, it satisfies the conditional expression 0.5 ≤ Y14 / Y15 ≤ 1.5, where Y14 is the perpendicular distance from the critical point on the object-side surface of the seventh lens 17 to the optical axis, and Y15 is the perpendicular distance from the critical point on the image-side surface of the seventh lens 17 to the optical axis.

[0047] Preferably, it satisfies the conditional expression Y16 / Y17 ≤ 3, where Y16 is the perpendicular distance from the critical point on the object-side surface of the eighth lens 18 to the optical axis, and Y17 is the perpendicular distance from the critical point on the image-side surface of the eighth lens 18 to the optical axis.

[0048] The present invention adopts an eight-piece lens combination. Through reasonable focal power matching, while ensuring high imaging quality of the lens, the overall length of the lens is effectively shortened, enabling the lens to meet the requirements of miniaturization. The reasonable parameter matching between the lenses makes the lens have the characteristic of a large aperture, meeting the shooting requirements of people in low-light environments.

[0049] First Embodiment, please refer to Figures 1-3 , a wide-angle large-aperture lens provided in the first embodiment of the present invention. The first lens 11 is set as a glass lens, and the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, and the eighth lens 18 are all set as plastic lenses. The relevant parameters of each lens in the wide-angle large-aperture lens are shown in Table 1-1, and the aspheric parameters of each lens in this embodiment are shown in Table 1-2.

[0050] Table 1-1

[0051]

[0052] Table 1-2

[0053]

[0054]

[0055] All the aspheric surfaces satisfy the following equation:

[0056]

[0057] Where: z represents the sagitta of the aspheric surface along the optical axis at a distance h from the optical axis to the surface, measured from the vertex of the aspheric surface; c represents the curvature of the vertex of the surface; K represents the conic coefficient; B, C, D, E, F, G, H represent the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surfaces, respectively. Each aspheric surface profile satisfies this formula.

[0058] In the first embodiment, the system focal length f = 6.81 mm, FNO = 1.65, the field of view angle is 91.47 degrees, and the total system length TOTR = 10.97. Table 1-3 shows the condition calculation results.

[0059] Table 1-3

[0060] Conditional expression Actual Result 0 ≤ TTL / OD ≤ 1.0 0.941 Complies with f1 / f ≥ 2.0 2.444 Complies with f6 / f ≤ 1.0 0.767 Complies with 0 ≤ SAG62 / CT6 ≤ 1.0 0.931 Complies with 0.5 ≤ Y14 / Y15 ≤ 1.5 0.777 Complies with 1.0 ≤ TTL / Tp ≤ 2.0 1.625 Complies with Td / ENPD ≤ 2.5 2.487 Complies with Y16 / Y17 ≤ 3.0 2.044 Complies with

[0061] For the second embodiment, please refer to Figures 4-6 as shown. A wide-angle large-aperture lens provided in the second embodiment of the present invention has the first lens 11 made of a glass lens, and the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, and the eighth lens 18 are all made of plastic lenses. The relevant parameters of each lens are shown in Table 2-1, and the aspheric surface parameters of each lens in this embodiment are shown in Table 2-2.

[0062] Table 2-1

[0063]

[0064]

[0065] Table 2-2

[0066]

[0067] The aspheric surfaces described above all satisfy the following equation:

[0068]

[0069] Where: z represents the sagitta of the aspheric surface along the optical axis at a distance h from the optical axis to the surface, measured from the vertex of the aspheric surface; c represents the curvature of the vertex of the surface; K represents the conic coefficient; B, C, D, E, F, G, H represent the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surfaces, respectively. Each aspheric surface profile satisfies this formula.

[0070] In the second embodiment, the system focal length f = 6.80 mm, FNO = 1.65, the field of view angle is 91.47 degrees, and the total system length TOTR = 10.90 mm. Table 2-3 shows the condition calculation results.

[0071] Table 2-3

[0072] Conditional expression Actual Result 0 ≤ TTL / OD ≤ 1.0 0.935 Complies with f1 / f ≥ 2.0 2.413 Complies with f6 / f ≤ 1.0 0.767 Complies with 0 ≤ SAG62 / CT6 ≤ 1.0 0.907 Complies with 0.5 ≤ Y14 / Y15 ≤ 1.5 0.826 Complies with 1.0 ≤ TTL / Tp ≤ 2.0 1.634 Complies with Td / ENPD ≤ 2.5 2.475 Complies with Y16 / Y17 ≤ 3.0 1.988 Complies with

[0073] For the third embodiment, please refer to Figures 7-9 as shown. In the third embodiment of the present invention, a wide-angle large-aperture lens is provided. The first lens 11 is set as a glass lens, and the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, the sixth lens 16, the seventh lens 17, and the eighth lens 18 are all set as plastic lenses. The relevant parameters of each lens are shown in Table 3-1, and the aspherical parameters of each lens in this embodiment are shown in Table 3-2.

[0074] Table 3-1

[0075]

[0076] Table 3-2

[0077]

[0078]

[0079] All the aspheres satisfy the following equation:

[0080]

[0081] Where: z represents the sagitta of the aspheric surface along the optical axis at a distance h from the optical axis to the surface, c represents the curvature of the vertex of the surface, K represents the conic coefficient, and B, C, D, E, F, G, H respectively represent the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients. The aspheric surface profiles of all satisfy this formula.

[0082] In the third embodiment, the system focal length f = 14.69 mm, FNO = 2.0, the field of view angle is 39.2 degrees, and the total system length TOTR = 15.86 mm. Table 3-3 shows the conditional calculation results.

[0083] Table 3-3

[0084] Conditional expression Actual Result 0 ≤ TTL / OD ≤ 1.0 0.922 Complies with f1 / f ≥ 2.0 2.266 Complies with f6 / f ≤ 1.0 0.771 Complies with 0 ≤ SAG62 / CT6 ≤ 1.0 0.945 Complies with 0.5 ≤ Y14 / Y15 ≤ 1.5 0.762 Complies with 1.0 ≤ TTL / Tp ≤ 2.0 1.604 Complies with Td / ENPD ≤ 2.5 2.481 Complies with Y16 / Y17 ≤ 3.0 1.941 Complies with

[0085] The above-described embodiments merely represent three implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A wide-angle large-aperture lens, which is composed of a diaphragm (10), a first lens (11), a second lens (12), a third lens (13), a fourth lens (14), a fifth lens (15), a sixth lens (16), a seventh lens (17), an eighth lens (18), and a flat glass (19) in sequence from the object side to the image plane (20); It is characterized in that: The first lens (11) is set as a convex-concave lens with positive optical power, the second lens (12) is set as a convex-concave meniscus lens with negative optical power, the third lens (13) is set as having positive optical power, the fourth lens (14) is set as having negative optical power, the fifth lens (15) is set as having negative optical power, the sixth lens (16) is set as a convex-concave lens with positive optical power, the seventh lens (17) is set as having negative optical power, and the eighth lens (18) is set as having negative optical power; It satisfies the conditional formula: Td / ENPD≤2.5, where Td is the distance on the optical axis from the object side of the first lens (11) to the image side of the eighth lens (18), and ENPD is the entrance pupil diameter of the wide-angle large-aperture lens; 1.0≤TTL / Tp≤2.0, where TTL is the total optical length of the wide-angle large-aperture lens, and Tp is the sum of the thicknesses of the first lens (11), the second lens (12), the third lens (13), the fourth lens (14), the fifth lens (15), the sixth lens (16), the seventh lens (17), and the eighth lens (18) on the optical axis.

2. The wide-angle large-aperture lens according to claim 1, wherein: It satisfies the conditional formula 0≤TTL / OD≤1.0, where OD is the maximum aperture of the lens.

3. A wide-angle large-aperture lens according to claim 1, wherein: It satisfies the conditional formula f1 / f≥2.0, where f1 is the focal length of the first lens (11), and f is the focal length of the wide-angle large-aperture lens.

4. A wide-angle large-aperture lens according to claim 1, characterized in that: It satisfies the conditional formula f6 / f≤1.0, where f6 is the focal length of the sixth lens (16), and f is the focal length of the wide-angle large-aperture lens.

5. A wide-angle large-aperture lens according to claim 1, characterized in that: It satisfies the conditional formula 0≤SAG62 / CT6≤1.0, where SAG62 is the distance on the optical axis from the intersection point of the image side surface of the sixth lens (16) and the optical axis to the vertex of the effective semi-aperture of the image side surface of the eighth lens (18), and CT6 is the maximum thickness of the sixth lens (16) on the optical axis.

6. A wide-angle large-aperture lens according to claim 1, characterized in that: It satisfies the conditional formula 0.5≤Y14 / Y15≤1.5, where Y14 is the vertical distance from the critical point on the object side surface of the seventh lens (17) to the optical axis, and Y15 is the vertical distance from the critical point on the image side surface of the seventh lens (17) to the optical axis.

7. A wide-angle large-aperture lens according to claim 1, characterized in that: It satisfies the conditional formula Y16 / Y17≤3, where Y16 is the vertical distance from the critical point on the object side surface of the eighth lens (18) to the optical axis, and Y17 is the vertical distance from the critical point on the image side surface of the eighth lens (18) to the optical axis.

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