Large-aperture low-distortion line scanning lens

Abstract

The utility model relates to a large-aperture low-distortion line scanning lens. The line scanning lens comprises a first convex-concave lens, a second convex-concave lens, a diaphragm, a third biconcave lens, a fourth biconvex lens, a fifth convex-concave lens and a sixth biconcave lens which are arranged in sequence. The first convex-concave lens comprises a first front mirror surface and a first rear mirror surface, the second convex-concave lens comprises a second front mirror surface and a second rear mirror surface, the third biconcave lens comprises a third front mirror surface and a third rear mirror surface, the fourth biconvex lens comprises a fourth front mirror surface and a fourth rear mirror surface, and the fifth convex-concave lens comprises a fifth front mirror surface and a fifth rear mirror surface. The sixth biconcave lens comprises a sixth front mirror surface and a sixth rear mirror surface; and the diaphragm is arranged at the third front mirror surface. Compared with the prior art, the utility model has the advantages of large aperture, low distortion, only 0.1% of optical distortion, capability of distinguishing all fields of view at 50Lp / mm, and the like.

Description

Technical Field

[0001] This utility model relates to a line scan lens, and more particularly to a large aperture, low distortion line scan lens. Background Technology

[0002] A line scan lens is an industrial lens used in conjunction with a line scan camera. Its imaging principle involves using a linear sensor to capture an image of the workpiece and then performing digital signal processing to achieve high-precision imaging. Line scan lenses are characterized by a large maximum image size, enabling them to capture images of fast-moving objects, and feature high scanning frequencies and fast exposure times. While typically having a medium field of view, line scan lenses offer high resolution and excellent image quality, and their use in inspection applications is becoming increasingly widespread.

[0003] However, the aperture of most line scanning lenses on the market is not large, with F-numbers generally greater than 2.8. This makes them less suitable for high-speed scanning and low-light environments, resulting in less accurate detection. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the existing technology and provide a large aperture, low distortion line scan lens.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] A large-aperture, low-distortion line scan lens, comprising a first convex-concave lens, a second convex-concave lens, an aperture stop, a third biconcave lens, a fourth biconvex lens, a fifth convex-concave lens, and a sixth biconcave lens arranged sequentially; the first convex-concave lens includes a first front mirror surface and a first rear mirror surface, the second convex-concave lens includes a second front mirror surface and a second rear mirror surface, the third biconcave lens includes a third front mirror surface and a third rear mirror surface, the fourth biconvex lens includes a fourth front mirror surface and a fourth rear mirror surface, the fifth convex-concave lens includes a fifth front mirror surface and a fifth rear mirror surface, and the sixth biconcave lens includes a sixth front mirror surface and a sixth rear mirror surface; the aperture stop is located at the third front mirror surface.

[0007] Further, the first convex-concave lens is a convex-concave lens with a refractive index of 1.50≤n1≤2.00; the second convex-concave lens is a convex-concave lens with a refractive index of 1.45≤n2≤1.95; the third biconcave lens is a biconcave lens with a refractive index of 1.50≤n3≤2.00; the fourth biconvex lens is a biconvex lens with a refractive index of 1.40≤n4≤1.85; the fifth convex-concave lens is a convex-concave lens with a refractive index of 1.5≤n5≤2.00; and the sixth biconcave lens is a biconcave lens with a refractive index of 1.50≤n6≤2.00.

[0008] Furthermore, the first convex-concave lens is a convex-concave lens with a focal length of 80mm≤f1≤86mm; the second convex-concave lens is a convex-concave lens with a focal length of 53mm≤f2≤59mm; the third biconcave lens is a biconcave lens with a focal length of -31mm≤f3≤-25mm; the fourth biconvex lens is a biconvex lens with a focal length of 36mm≤f4≤42mm; the fifth convex-concave lens is a convex-concave lens with a focal length of 93mm≤f5≤100mm; and the sixth biconcave lens is a biconcave lens with a focal length of -39mm≤f6≤-33mm.

[0009] Furthermore, the line scan lens is a line scan lens that satisfies the following conditions: 1.4≤f1 / Fw≤2.0, 0.9≤f2 / Fw≤1.4, -0.9≤f3 / Fw≤-0.3, 0.5≤f4 / Fw≤1.1, 1.7≤f5 / Fw≤2.3, -1.0≤f6 / Fw≤-0.5; where Fw is the focal length of the line scan lens.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] This invention achieves a line scan lens with a focal length of 48.43mm, large aperture, and low distortion by combining different lenses. The optical system of this line scan lens has an F=2.0 and an optical distortion of only 0.1%. It can resolve all fields of view at 50Lp / mm, resulting in more accurate detection results and better adaptability to high-speed scanning and low-light environment detection scenarios. Moreover, it uses common materials, has a simple structure, and is low in cost. Attached Figure Description

[0012] Figure 1 This is a structural schematic diagram of the present invention;

[0013] Figure 2 The MTF curve provided by this utility model at a resolution of 50 line pairs / mm;

[0014] Figure 3 The distortion curve diagram provided for this utility model;

[0015] Figure 4 The relative illumination curve provided for this utility model.

[0016] The labels in the diagram indicate:

[0017] 1. First convex-concave lens; 2. Second convex-concave lens; 3. Aperture stop; 4. Third biconcave lens; 5. Fourth biconvex lens; 6. Fifth convex-concave lens; 7. Sixth biconcave lens; L1. First front mirror; L2. First rear mirror; L3. Second front mirror; L4. Second rear mirror; L5. Third front mirror; L6. Third rear mirror; L7. Fourth front mirror; L8. Fourth rear mirror; L9. Fifth front mirror; L10. Fifth rear mirror; L11. Sixth front mirror; L12. Sixth rear mirror. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0020] like Figure 1 As shown, this utility model discloses a large aperture, low distortion line scan lens with a focal length of 48.43mm, a working distance of 572.777mm, an image size of 31mm, and a total optical length of 650mm. The line scanning lens, from object to image, comprises a first convex-concave lens 1, a second convex-concave lens 2, an aperture stop 3, a third biconcave lens 4, a fourth biconvex lens 5, a fifth convex-concave lens 6, and a sixth biconcave lens 7 arranged sequentially. The first convex-concave lens 1 includes a first front mirror surface L1 and a first rear mirror surface L2; the second convex-concave lens 2 includes a second front mirror surface L3 and a second rear mirror surface L4; the third biconcave lens 4 includes a third front mirror surface L5 and a third rear mirror surface L6; the fourth biconvex lens 5 includes a fourth front mirror surface L7 and a fourth rear mirror surface L8; the fifth convex-concave lens 6 includes a fifth front mirror surface L9 and a fifth rear mirror surface L10; and the sixth biconcave lens 7 includes a sixth front mirror surface L11 and a sixth rear mirror surface L12. The aperture stop 3 is located at the third front mirror surface L5.

[0021] The refractive indices of the first convex-concave lens 1 to the sixth biconcave lens 7 sequentially satisfy the following conditions: 1.50≤n1≤2.00, 1.45≤n2≤1.95, 1.50≤n3≤2.00, 1.40≤n4≤1.85, 1.5≤n5≤2.00, and 1.50≤n6≤2.00 for the biconcave lens. Wherein, n1 represents the refractive index of the first convex-concave lens 1, n2 represents the refractive index of the second convex-concave lens 2, n3 represents the refractive index of the third biconcave lens 4, n4 represents the refractive index of the fourth biconvex lens 5, n5 represents the refractive index of the fifth convex-concave lens 6, and n6 represents the refractive index of the sixth biconcave lens 7.

[0022] The focal lengths of the first convex-concave lens 1 to the sixth biconcave lens 7 sequentially satisfy the following conditions: 80mm≤f1≤86mm, 53mm≤f2≤59mm, -31mm≤f3≤-25mm, 36mm≤f4≤42mm, 93mm≤f5≤100mm, -39mm≤f6≤-33mm; the linear scanning lens satisfies the following conditions: 1.4≤f1 / Fw≤2.0, 0.9≤f2 / Fw≤1.4, -0.9≤f1 / Fw ... f3 / Fw≤-0.3, 0.5≤f4 / Fw≤1.1, 1.7≤f5 / Fw≤2.3, -1.0≤f6 / Fw≤-0.5; where f1 is the focal length of the first convex-concave lens 1, f2 is the focal length of the second convex-concave lens 2, f3 is the focal length of the third biconcave lens 4, f4 is the focal length of the fourth biconvex lens 5, f5 is the focal length of the fifth convex-concave lens 6, f6 is the focal length of the sixth biconcave lens 7, and Fw is the focal length of the line scan lens.

[0023] The optical parameters of each of the six lenses are shown in Table 1 below.

[0024] Table 1 Optical parameters of each mirror surface of the lens

[0025]

[0026] like Figure 2 The figure shown is the MTF curve of this invention at a resolution of 50 line pairs / mm. Figure 3 This is a distortion curve diagram of this utility model. Figure 4 The relative illumination curve shows that this invention has a larger aperture and lower distortion. The optical system of this invention has an F=2.0 aperture and an optical distortion of only 0.1%. All fields of view can be resolved at 50 Lp / mm, resulting in more accurate detection and better adaptability to high-speed scanning and low-light environment detection scenarios.

[0027] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A large-aperture, low-distortion line-scan lens, characterized in that, The line scan lens includes a first convex-concave lens (1), a second convex-concave lens (2), an aperture stop (3), a third biconcave lens (4), a fourth biconvex lens (5), a fifth convex-concave lens (6), and a sixth biconcave lens (7) arranged sequentially. The first convex-concave lens (1) includes a first front mirror (L1) and a first rear mirror (L2), the second convex-concave lens (2) includes a second front mirror (L3) and a second rear mirror (L4), the third biconcave lens (4) includes a third front mirror (L5) and a third rear mirror (L6), the fourth biconvex lens (5) includes a fourth front mirror (L7) and a fourth rear mirror (L8), the fifth convex-concave lens (6) includes a fifth front mirror (L9) and a fifth rear mirror (L10), and the sixth biconcave lens (7) includes a sixth front mirror (L11) and a sixth rear mirror (L12). The aperture stop (3) is located at the third front mirror (L5).

2. The large-aperture, low-distortion line scan lens according to claim 1, characterized in that, The first convex-concave lens (1) is a convex-concave lens with a refractive index of 1.50≤n1≤2.00; the second convex-concave lens (2) is a convex-concave lens with a refractive index of 1.45≤n2≤1.95; the third biconcave lens (4) is a biconcave lens with a refractive index of 1.50≤n3≤2.00; the fourth biconvex lens (5) is a biconvex lens with a refractive index of 1.40≤n4≤1.85; the fifth convex-concave lens (6) is a convex-concave lens with a refractive index of 1.5≤n5≤2.00; and the sixth biconcave lens (7) is a biconcave lens with a refractive index of 1.50≤n6≤2.

00.

3. A large-aperture, low-distortion line-scan lens according to claim 2, characterized in that, The first convex-concave lens (1) is a convex-concave lens with a focal length of 80mm≤f1≤86mm; the second convex-concave lens (2) is a convex-concave lens with a focal length of 53mm≤f2≤59mm; the third biconcave lens (4) is a biconcave lens with a focal length of -31mm≤f3≤-25mm; the fourth biconvex lens (5) is a biconvex lens with a focal length of 36mm≤f4≤42mm; the fifth convex-concave lens (6) is a convex-concave lens with a focal length of 93mm≤f5≤100mm; and the sixth biconcave lens (7) is a biconcave lens with a focal length of -39mm≤f6≤-33mm.

4. A large-aperture, low-distortion line-scan lens according to claim 3, characterized in that, The line scan lens is a line scan lens that satisfies the following conditions: 1.4≤f1 / Fw≤2.0, 0.9≤f2 / Fw≤1.4, -0.9≤f3 / Fw≤-0.3, 0.5≤f4 / Fw≤1.1, 1.7≤f5 / Fw≤2.3, -1.0≤f6 / Fw≤-0.5; where Fw is the focal length of the line scan lens.

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