A fixed-focus lens

Abstract

An embodiment of the present invention provides a fixed-focus lens, which relates to the technology of optical lenses. An embodiment of the present invention provides a fixed-focus lens, including 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 arranged in sequence along the optical axis from the object side to the image side; the first lens, the fourth lens, and the fifth lens all have negative optical powers, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens all have positive optical powers. An embodiment of the present invention provides a fixed-focus lens to achieve an optical lens with a large target surface, a large aperture, small distortion, and meeting the requirements of 4K high-definition imaging.

Description

Technical Field

[0001] The present invention relates to the technology of optical lenses, and particularly to a fixed-focus lens. Background Art

[0002] With the rapid development of social economy, intelligent transportation systems are being more and more widely used. Under the condition of continuous technological progress, the market has higher and higher requirements for performance. From visible in the past to high definition now, the target surface of imaging chips is getting larger and the demand for light transmission brightness is getting stronger. Therefore, corresponding requirements and improvements are also put forward for optical imaging systems.

[0003] At present, traffic monitoring lenses on the market often cannot balance performance such as high definition, large target surface, and large aperture. Most of the intelligent transportation imaging lenses launched by manufacturers are generally adapted to 2 / 3-inch chips, and some can be adapted to 1 inch, but it is very rare to be adapted to chips with a larger target surface, such as 4 / 3 inches. Summary of the Invention

[0004] An embodiment of the present invention provides a fixed-focus lens to realize an optical lens with a large target surface, a large aperture, small distortion and meeting the requirements of 4K high-definition imaging.

[0005] An embodiment of the present invention provides a fixed-focus lens, which includes 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 arranged in sequence along the optical axis from the object side to the image side direction;

[0006] The first lens, the fourth lens and the fifth lens all have negative optical powers, and the second lens, the third lens, the sixth lens, the seventh lens and the eighth lens all have positive optical powers.

[0007] Optionally, the second lens is a biconvex lens, the third lens is a meniscus lens, the fourth lens is a meniscus lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a meniscus lens or a biconvex lens, and the eighth lens is a biconvex lens or a meniscus lens.

[0008] Optionally, the optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, the optical power of the sixth lens is φ6, the optical power of the seventh lens is φ7, the optical power of the eighth lens is φ8, and the optical power of the fixed-focus lens is φ, satisfying:

[0009] 0.005 ≤ |φ1 / φ| ≤ 0.057;

[0010] 0.008 ≤ |φ2 / φ| ≤ 0.052;

[0011] 0.003 ≤ |φ3 / φ| ≤ 0.055;

[0012] 0.010 ≤ |φ4 / φ| ≤ 0.150;

[0013] 0.014 ≤ |φ5 / φ| ≤ 0.088;

[0014] 0.007 ≤ |φ6 / φ| ≤ 0.063;

[0015] 0.001 ≤ |φ7 / φ| ≤ 0.049;

[0016] 0.002 ≤ |φ8 / φ| ≤ 0.057.

[0017] Optionally, the refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, and the refractive index of the eighth lens is n8, satisfying:

[0018] 1.43 ≤ n1 ≤ 2.01;

[0019] 1.45 ≤ n2 ≤ 2.01;

[0020] 1.62 ≤ n3 ≤ 2.01;

[0021] 1.34 ≤ n4 ≤ 1.77;

[0022] 1.65 ≤ n5 ≤ 2.01;

[0023] 1.47 ≤ n6 ≤ 1.88;

[0024] 1.43 ≤ n7 ≤ 2.01;

[0025] 1.51 ≤ n8 ≤ 2.01.

[0026] Optionally, the Abbe number of the first lens is v1, the Abbe number of the second lens is v2, the Abbe number of the third lens is v3, the Abbe number of the fourth lens is v4, the Abbe number of the fifth lens is v5, the Abbe number of the sixth lens is v6, the Abbe number of the seventh lens is v7, and the Abbe number of the eighth lens is v8, satisfying:

[0027] 20.0 ≤ v1 ≤ 82.0;

[0028] 28.0 ≤ v2 ≤ 95.0;

[0029] 19.8 ≤ v3 ≤ 78.0;

[0030] 21.0 ≤ v4 ≤ 90.0;

[0031] 19.5 ≤ v5 ≤ 62.0;

[0032] 58.0 ≤ v6 ≤ 85.0;

[0033] 36.0 ≤ v7 ≤ 95.0;

[0034] 23.5 ≤ v8 ≤ 92.0.

[0035] Optionally, it further includes a diaphragm, and the diaphragm is located between the fourth lens and the fifth lens.

[0036] Optionally, the aperture of the fixed-focus lens is F, and the focal length of the fixed-focus lens is f, satisfying:

[0037] 0.01 ≤ F / f ≤ 0.15.

[0038] Optionally, the image plane diameter of the fixed-focus lens is IC, and the overall optical length of the fixed-focus lens is TTL, satisfying:

[0039] 0.1 ≤ IC / TTL ≤ 0.5.

[0040] Optionally, the field of view angle of the fixed-focus lens is FOV, and the entrance pupil diameter of the fixed-focus lens is EP, satisfying:

[0041] 1.1 ≤ FOV / EP ≤ 8.6.

[0042] Optionally, the fixed-focus lens is an intelligent transportation lens.

[0043] The fixed-focus lens provided by the embodiment of the present invention uses 8 lenses. Among them, the first lens, the fourth lens, and the fifth lens all have negative optical powers, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens all have positive optical powers. The embodiment of the present invention provides a fixed-focus lens to realize an optical lens with a large target surface, a large aperture, small distortion, and meeting the requirements of 4K high-definition imaging. This lens supports a maximum target surface of 4 / 3 inches at a relatively low cost, the aperture number satisfies 1.1 < F < 1.8, the field of view angle satisfies the range of 10° to 70°, and it meets the imaging requirements when used in an environment of -40°C to 80°C. Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of a fixed-focus lens in the first embodiment;

[0045] Figure 2 It is a spherical aberration curve graph of a fixed-focus lens in the first embodiment;

[0046] Figure 3: is a ray fan diagram of a fixed-focus lens in the first embodiment;

[0047] Figure 4 is a spot diagram of a fixed-focus lens in the first embodiment;

[0048] Figure 5 : is a field curvature distortion diagram of a fixed-focus lens in the first embodiment;

[0049] Figure 6 Schematic diagram of the structure of a fixed-focus lens in the second embodiment;

[0050] Figure 7 is a spherical aberration curve diagram of a fixed-focus lens in the second embodiment;

[0051] Figure 8 This is a ray fan diagram of a fixed-focus lens in the second embodiment;

[0052] Figure 9 is a spot diagram of a fixed-focus lens in the second embodiment;

[0053] Figure 10 This is a field curvature distortion diagram of a fixed-focus lens in the second embodiment;

[0054] Figure 11 Schematic diagram of the structure of a fixed-focus lens in the third embodiment;

[0055] Figure 12 is a spherical aberration curve diagram of a fixed-focus lens in the third embodiment;

[0056] Figure 13 This is a ray fan diagram of a fixed-focus lens in the third embodiment;

[0057] Figure 14 This is a spot diagram of a fixed-focus lens in the third embodiment;

[0058] Figure 15 This is a field curvature distortion diagram of a fixed-focus lens in the third embodiment. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0060] Example 1

[0061] Figure 1 This is a structural diagram of a fixed-focus lens in the first embodiment, referring to Figure 1, the fixed-focus lens includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8 arranged in sequence along the optical axis from the object side to the image side. The first lens 1, the fourth lens 4, and the fifth lens 5 all have negative optical powers, and the second lens 2, the third lens 3, the sixth lens 6, the seventh lens 7, and the eighth lens 8 all have positive optical powers.

[0062] The fixed-focus lens provided by the embodiment of the present invention uses 8 lenses. Among them, the first lens 1, the fourth lens 4, and the fifth lens 5 all have negative optical powers, and the second lens 2, the third lens 3, the sixth lens 6, the seventh lens 7, and the eighth lens 8 all have positive optical powers. The embodiment of the present invention provides a fixed-focus lens to achieve an optical lens with a large target surface, a large aperture, small distortion, and meeting the requirements of 4K high-definition imaging. This lens supports a maximum target surface of 4 / 3 inches at a relatively low cost, the aperture number satisfies 1.1 < F < 1.8, the field of view angle satisfies the range of 10° to 70°, and it meets the imaging requirements when used in an environment of -40°C to 80°C.

[0063] Optionally, the shape of the first lens 1 is not limited. The first lens 1 can be one of a biconcave lens, a meniscus lens, and a plano-concave lens.

[0064] Optionally, the second lens 2 is a biconvex lens, the third lens 3 is a meniscus lens, the fourth lens 4 is a meniscus lens, the fifth lens 5 is a biconcave lens, the sixth lens 6 is a biconvex lens, the seventh lens 7 is a meniscus lens or a biconvex lens, and the eighth lens 8 is a biconvex lens or a meniscus lens.

[0065] Optionally, the optical power of the first lens 1 is φ1, the optical power of the second lens 2 is φ2, the optical power of the third lens 3 is φ3, the optical power of the fourth lens 4 is φ4, the optical power of the fifth lens 5 is φ5, the optical power of the sixth lens 6 is φ6, the optical power of the seventh lens 7 is φ7, the optical power of the eighth lens 8 is φ8, and the optical power of the fixed-focus lens is φ, satisfying: 0.005 ≤ |φ1 / φ| ≤ 0.057, 0.008 ≤ |φ2 / φ| ≤ 0.052, 0.003 ≤ |φ3 / φ| ≤ 0.055, 0.010 ≤ |φ4 / φ| ≤ 0.150, 0.014 ≤ |φ5 / φ| ≤ 0.088, 0.007 ≤ |φ6 / φ| ≤ 0.063, 0.001 ≤ |φ7 / φ| ≤ 0.049, 0.002 ≤ |φ8 / φ| ≤ 0.057.

[0066] Optionally, the refractive index of the first lens 1 is n1, the refractive index of the second lens 2 is n2, the refractive index of the third lens 3 is n3, the refractive index of the fourth lens 4 is n4, the refractive index of the fifth lens 5 is n5, the refractive index of the sixth lens 6 is n6, the refractive index of the seventh lens 7 is n7, and the refractive index of the eighth lens 8 is n8, satisfying: 1.43 ≤ n1 ≤ 2.01, 1.45 ≤ n2 ≤ 2.01, 1.62 ≤ n3 ≤ 2.01, 1.34 ≤ n4 ≤ 1.77,

[0067] 1.65 ≤ n5 ≤ 2.01, 1.47 ≤ n6 ≤ 1.88, 1.43 ≤ n7 ≤ 2.01, 1.51 ≤ n8 ≤ 2.01.

[0068] Optionally, the dispersion coefficient of the first lens 1 is v1, the dispersion coefficient of the second lens 2 is v2, the dispersion coefficient of the third lens 3 is v3, the dispersion coefficient of the fourth lens 4 is v4, the dispersion coefficient of the fifth lens 5 is v5, the dispersion coefficient of the sixth lens 6 is v6, the dispersion coefficient of the seventh lens 7 is v7, and the dispersion coefficient of the eighth lens 8 is v8, satisfying: 20.0 ≤ v1 ≤ 82.0, 28.0 ≤ v2 ≤ 95.0, 19.8 ≤ v3 ≤ 78.0, 21.0 ≤ v4 ≤ 90.0, 19.5 ≤ v5 ≤ 62.0, 58.0 ≤ v6 ≤ 85.0, 36.0 ≤ v7 ≤ 95.0, 23.5 ≤ v8 ≤ 92.0.

[0069] Optionally, the fixed-focus lens further includes a diaphragm 9, and the diaphragm 9 is located between the fourth lens 4 and the fifth lens 5.

[0070] Optionally, the aperture of the fixed-focus lens is F, and the focal length of the fixed-focus lens is f, satisfying: 0.01 ≤ F / f ≤ 0.15.

[0071] Optionally, the image plane diameter of the fixed-focus lens is IC, and the overall optical length of the fixed-focus lens is TTL, satisfying: 0.1 ≤ IC / TTL ≤ 0.5.

[0072] Optionally, the field of view angle of the fixed-focus lens is FOV, and the entrance pupil diameter of the fixed-focus lens is EP, satisfying: 1.1 ≤ FOV / EP ≤ 8.6.

[0073] Optionally, the fixed-focus lens is an intelligent transportation lens, and the fixed-focus lens is applied to intelligent transportation.

[0074] Table 1 shows a set of design values of the fixed-focus lens in the first embodiment

[0075] Surface Serial Number Surface Type Radius of Curvature (mm) Thickness (mm) Refractive Index Dispersion Coefficient 1 Spherical Surface -1639.87 2.00 1.50 44.4 2 Spherical Surface 27.50 28.62 3 Spherical Surface 47.60 6.00 1.68 87.0 4 Spherical Surface -85.18 2.01 5 Spherical Surface 26.16 7.27 2.01 30.0 6 Spherical Surface 29.29 3.13 1.53 75.0 7 Spherical Surface 16.06 4.24 STOP PL Infinity 9.76 9 Spherical Surface -18.94 2.51 1.78 26.1 10 Spherical Surface 60.56 6.41 1.60 75.0 11 Spherical Surface -26.55 0.32 12 Spherical Surface 374.47 4.33 1.55 51.9 13 Spherical Surface -45.40 4.77 14 Spherical Surface 56.38 10.62 2.01 73.0 15 Spherical Surface -278.94 17.89

[0076] Table 1 shows a set of design values of the fixed-focus lens in the first embodiment. The specific numerical values can be adjusted according to product requirements and are not limitations on the embodiments of the present invention. The fixed-focus lens shown in Table 1 can beFigure 1 As shown. A lens generally includes two surfaces, and each surface is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, the surface number "1" represents the front surface of the first lens 1, the surface number "2" represents the rear surface of the first lens 1, and so on, which will not be elaborated here. It should be noted that "STOP" in the "Surface Number" column represents the plane where the diaphragm 9 is located. "PL" in the "Surface Type" column represents a plane. The radius of curvature represents the degree of curvature of the lens surface. A positive radius of curvature value indicates that the center of curvature is on the image side near the surface, and a negative radius of curvature value represents that the center of curvature is on the side away from the image side of the surface. The value in the "Thickness" column represents the axial distance from the current surface to the next surface. The "Refractive Index" column represents the refractive index of the medium between the current surface and the next surface. The space in the "Refractive Index" column is the refractive index of air, and the refractive index of air is 1. The dispersion coefficient represents the dispersion characteristics of the material between the current surface and the next surface to light, and the space represents that the current position is air.

[0077] According to the design values of the fixed-focus lens shown in Table 1, the aperture of the fixed-focus lens is 1.5, the focal length is 30.2 mm, the image plane diameter is 22.6 mm, the diagonal field of view angle is 43°, and the optical distortion is -5.2%.

[0078] Example Two

[0079] Table 2 shows a set of design values of the fixed-focus lens in Example Two

[0080]

[0081]

[0082] Table 2 shows a set of design values of the fixed-focus lens in Example Two. Its specific numerical values can be adjusted according to product requirements, and it is not a limitation to the embodiments of the present invention. The fixed-focus lens shown in Table 2 can be Figure 6 as shown in

[0083] According to the design values of the fixed-focus lens shown in Table 2, the aperture of the fixed-focus lens is 1.19, the focal length is 30.2 mm, the image plane diameter is 22.6 mm, the diagonal field of view angle is 43°, and the optical distortion is -5.1%.

[0084] Example Three

[0085] Table 3 shows a set of design values of the fixed-focus lens in Example Three

[0086]

[0087]

[0088] Table 3 shows a set of design values for the fixed-focus lens in the third embodiment. The specific numerical values can be adjusted according to product requirements and do not limit the embodiments of the present invention. The fixed-focus lens shown in Table 3 can be Figure 11 as shown in

[0089] According to the design values of the fixed-focus lens shown in Table 3, the aperture of the fixed-focus lens is 1.62, the focal length is 30.2 mm, the image plane diameter is 22.7 mm, the diagonal field of view angle is 50°, and the optical distortion is -18.9%.

[0090] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, combinations with each other, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A fixed-focus lens, characterized in that, It includes 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 arranged in sequence along the optical axis from the object side to the image side direction; The first lens, the fourth lens, and the fifth lens all have negative optical powers, and the second lens, the third lens, the sixth lens, the seventh lens, and the eighth lens all have positive optical powers; The second lens is a biconvex lens, the third lens is a meniscus lens, the fourth lens is a meniscus lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a meniscus lens or a biconvex lens, and the eighth lens is a biconvex lens or a meniscus lens; The optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the fourth lens is φ4, the optical power of the fifth lens is φ5, the optical power of the sixth lens is φ6, the optical power of the seventh lens is φ7, the optical power of the eighth lens is φ8, and the optical power of the fixed-focus lens is φ, satisfying: 0.005 ≤ |φ1 / φ| ≤ 0.057; 0.008 ≤ |φ2 / φ| ≤ 0.052; 0.003 ≤ |φ3 / φ| ≤ 0.055; 0.010 ≤ |φ4 / φ| ≤ 0.150; 0.014 ≤ |φ5 / φ| ≤ 0.088; 0.007 ≤ |φ6 / φ| ≤ 0.063; 0.001 ≤ |φ7 / φ| ≤ 0.049; 0.002 ≤ |φ8 / φ| ≤ 0.

057.

2. The fixed-focus lens according to claim 1, wherein The refractive index of the first lens is n1, the refractive index of the second lens is n2, the refractive index of the third lens is n3, the refractive index of the fourth lens is n4, the refractive index of the fifth lens is n5, the refractive index of the sixth lens is n6, the refractive index of the seventh lens is n7, the refractive index of the eighth lens is n8, satisfying: 1.43≤n1≤2.01； 1.45≤n2≤2.01； 1.62≤n3≤2.01； 1.34≤n4≤1.77； 1.65≤n5≤2.01； 1.47≤n6≤1.88； 1.43≤n7≤2.01； 1.51≤n8≤2.01。 3. The fixed-focus lens according to claim 1, characterized in that, The Abbe number of the first lens is v1, the Abbe number of the second lens is v2, the Abbe number of the third lens is v3, the Abbe number of the fourth lens is vx4, the Abbe number of the fifth lens is v5, the Abbe number of the sixth lens is v6, the Abbe number of the seventh lens is v7, the Abbe number of the eighth lens is v8, satisfying: 20.0≤v1≤82.0； 28.0≤v2≤95.0； 19.8≤v3≤78.0； 21.0≤v4≤90.0； 19.5≤v5≤62.0； 58.0≤v6≤85.0； 36.0≤v7≤95.0； 23.5≤v8≤92.0。 4. The fixed-focus lens according to claim 1, characterized in that, It further includes a diaphragm, and the diaphragm is located between the fourth lens and the fifth lens.

5. The fixed-focus lens according to claim 1, characterized in that, The aperture of the fixed-focus lens is F, and the focal length of the fixed-focus lens is f, satisfying: 0.01 ≤ F / f ≤ 0.

15.

6. The fixed-focus lens according to claim 1, characterized in that, The image plane diameter of the fixed-focus lens is IC, and the overall optical length of the fixed-focus lens is TTL, satisfying: 0.1 ≤ IC / TTL ≤ 0.

5.

7. The fixed-focus lens according to claim 1, wherein, The field of view angle of the fixed-focus lens is FOV, and the entrance pupil diameter of the fixed-focus lens is EP, satisfying: 1.1 ≤ FOV / EP ≤ 8.

6.

8. The fixed-focus lens according to claim 1, wherein, The fixed-focus lens is an intelligent transportation lens.

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