Wide working distance high performance line scan lens

Abstract

This invention provides a wide working distance, high-performance line scanning lens. A first lens group G1 and a second lens group G2 are sequentially arranged from the object side to the image side. During focusing, both the first lens group G1 and the second lens group G2 move along the optical axis. Focusing of the lens can be achieved by changing the distance between the first lens group G1 and the second lens group G2. This lens, while satisfying the wide working distance requirement, features low distortion and high resolution, meeting the needs of high-pixel, large-area sensors. In different field-of-view detection applications, this lens can simultaneously address the requirements of optical distortion, field of view, and working efficiency, thus meeting the requirements of high-performance imaging.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more specifically to a wide working distance, high-performance line scan lens. Background Technology

[0002] In the context of industrial automation, machine vision systems occupy a crucial position. Their primary function is to use machines to measure, assess, and detect defects in target parts, thereby reducing or eliminating misjudgments that occur during human operation and improving measurement accuracy and stability. In the field of high-precision detection of large targets, the size of the detector necessitates the use of line scan lenses for imaging. During scanning, the working distance of the line scan lens needs to be adjusted to achieve high-performance imaging at different target sizes and resolutions.

[0003] Most existing line scan lenses are modified from camera lenses, making them unsuitable for machine vision applications. They commonly suffer from optical distortion, and the field of view and working distance cannot be simultaneously optimized, often resulting in compromises in production applications. Particularly in different field-of-view inspections, the common practice of using a single focusing group causes asynchronous image plane movement between the peripheral and central fields of view, leading to poor peripheral field-of-view performance and failing to meet high-performance imaging requirements. Therefore, the development of high-performance line scan lenses with wide working distances is even more urgent. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a wide working distance, high-performance line scan lens. While meeting the requirements of a wide working distance, this lens features low distortion and high resolution, meeting the needs of high-pixel, large-area photosensitive sensors. In different field-of-view detection applications, this lens can simultaneously address the requirements of optical distortion, field of view, and working conditions, thus satisfying the requirements of high-performance imaging.

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

[0006] This invention provides a wide working distance high-performance line scan lens, which has a first lens group G1 and a second lens group G2 arranged sequentially from the object side to the image side. During the focusing process, both the first lens group G1 and the second lens group G2 move along the optical axis. The lens can be focused by changing the interval between the first lens group G1 and the second lens group G2.

[0007] This invention provides a wide working distance, high-performance line scan lens. While meeting the wide working distance requirement, the lens has low distortion and high resolution, which is suitable for use with high-pixel, large-area photosensitive sensors. In different field-of-view detection applications, the lens can simultaneously take into account the requirements of optical distortion, field of view, and working conditions, thus meeting the requirements of high-performance imaging.

[0008] As a preferred technical solution, the second lens group G2 satisfies the following condition:

[0009]

[0010] Where, β F β is the lateral magnification of the second lens group G2 at its farthest working distance. N This is the lateral magnification of the second lens group G2 at the closest working distance.

[0011] As a preferred technical solution, the second lens group G2 satisfies the following condition:

[0012]

[0013] Where f1 is the focal length of the first lens group G1 and f2 is the focal length of the second lens group G2.

[0014] As a preferred technical solution, the first lens group G1 satisfies the following condition:

[0015]

[0016] Where f is the focal length of the line scan lens, and f1 is the focal length of the first lens group G1.

[0017] As a preferred technical solution, the cemented lens composed of optical elements L21 with positive optical power and optical elements L22 with negative optical power arranged sequentially from the object side in the second lens group G2 satisfies the following condition:

[0018] n 21 -n 22 ≥0.10

[0019]

[0020] Where, n 21 and n 22 The optical elements L are respectively represented by 21 The d-line refractive index and the optical element L 22 d-line refractive index; υ 21 and υ 22 The optical elements L are respectively represented by 21 The Abbe number and the optical element L 22 Abbe number.

[0021] As a preferred technical solution, the wide working distance high-performance line scan lens satisfies the following condition:

[0022]

[0023] Among them, TTLF The total optical length of the line scan lens at its farthest working distance is TTL. N The total optical length of the line scan lens at its closest working distance.

[0024] As a preferred technical solution, the first lens group G1 includes a front lens group GF, an aperture stop ST, and a rear lens group GB arranged sequentially from the object plane to the image plane. During focusing, the front lens group GF, the aperture stop ST, and the rear lens group GB move synchronously along the optical axis.

[0025] As a preferred technical solution, the front lens group GF includes a first optical element and a second optical element arranged sequentially from the object plane to the image plane, wherein the second optical element is a cemented lens group.

[0026] As a preferred technical solution, the front lens group GF includes a first optical element, a second optical element, a third optical element, a fourth optical element and a fifth optical element arranged sequentially from the object plane to the image plane, wherein the third optical element is a cemented lens group.

[0027] As a preferred technical solution, the second lens group G2 has an image plane IMA on the side near the image side.

[0028] This invention provides a wide working distance, high-performance line scan lens, which has the following advantages:

[0029] 1) The present invention provides a wide working distance high-performance line scan lens. During the focusing process, the first lens group G1 and the second lens group G2 both move along the optical axis. This enables the lens to achieve a change in the lateral magnification of the second lens group G2 by changing the interval between the first lens group G1 and the second lens group G2 while focusing the entire lens group. This compensates for the offset of the image plane and meets the requirement of high-quality imaging under a wide working distance.

[0030] 2) This invention provides a wide working distance, high-performance line scan lens, when... At the closest working distance, the lateral magnification of the second lens group is too large, resulting in a longer back focal length for the line scan lens. This excessively long overall optical system length is not optimal. At the furthest working distance, the lateral magnification of the second lens group is too large, resulting in excessive movement during focusing and a decrease in image quality, which is not the optimal solution; when the second lens group G2 satisfies This conditional expression specifies the range of the ratio between the lateral magnification of the second lens group and the difference between 1 at the farthest and closest working distances. By reasonably selecting the lateral magnification of the second lens group, the lens can maintain good imaging performance within a certain working distance and achieve high-quality imaging at a wide working distance.

[0031] 3) This invention provides a wide working distance, high-performance line scan lens, when... If the optical focal length of the first lens group is too small, its contribution to the optical focal length is too small, and it cannot meet the requirements for large target imaging; when The first lens group has too large an optical focal length, resulting in excessive aberrations such as spherical aberration and coma, leading to decreased imaging performance and making it a non-optimal solution. When the second lens group G2 satisfies the condition... The condition ≤0.9 specifies the range of the ratio between the focal lengths of the second lens group G2 and the first lens group G1, which enables the line scan lens to have a large target surface while meeting the requirements of miniaturization.

[0032] 4) This invention provides a wide working distance, high-performance line scan lens, when... The focusing sensitivity of the first lens group is too high, resulting in excessive aberrations such as image plane curvature and astigmatism, leading to decreased imaging performance and making it a suboptimal solution; when If the focusing sensitivity of the first lens group is too low, the focusing interval will be too long, making it impossible to achieve high-performance imaging over a wide working distance; when the first lens group G1 satisfies This conditional expression specifies the range of the ratio between the square of the focal length of the entire lens group and the first lens group G1, which enables the line scan lens to have a wide working distance while having a small adjustment interval, thus meeting the requirements of high-precision focusing.

[0033] 5) This invention provides a wide working distance, high-performance line scan lens, when n 21 -n 22 When the refractive index difference is less than 0.10, the difference between the positive and negative lenses is too small, resulting in insufficient spherical aberration compensation and poor peripheral imaging performance; when... If the Abbe number of the positive and negative lens materials is too small, insufficient correction of positional chromatic aberration will result in poor central imaging performance. When the second lens group satisfies... By reasonably setting the refractive index and Abbe number of the glass material with positive and negative optical power in the cemented lens of the second lens group, the positional chromatic aberration and magnification chromatic aberration of the optical system are controlled within a certain range, achieving high-quality imaging while meeting the wide working distance requirement.

[0034] 6) The present invention provides a wide working distance high-performance line scan lens, wherein the wide working distance high-performance line scan lens satisfies The conditional formula specifies the range of the ratio between the total optical length at the farthest working distance and the total optical length at the closest working distance. This formula can effectively control the variation of the total optical length of the line scan lens to meet the requirements of high-performance imaging while satisfying wide working distance imaging. By controlling the total optical length at different working distances, the miniaturization of the line scan lens can be achieved while realizing wide working distance imaging. Attached Figure Description

[0035] Figure 1A schematic diagram of the structure of the wide working distance high-performance line scan lens provided in Example 1 (object side is at the leftmost position, image side is at the rightmost position);

[0036] Figure 2 Aberration diagrams of the wide working distance high-performance line scan lens provided in Example 1;

[0037] Figure 3 A schematic diagram of the structure of the wide working distance high-performance line scan lens provided in Example 2 (object side is at the leftmost position, image side is at the rightmost position);

[0038] Figure 4 Aberration diagrams of the wide working distance high-performance line scan lens provided in Example 2;

[0039] Figure 5 A schematic diagram of the structure of the wide working distance high-performance line scan lens provided in Example 3 (object side is at the leftmost position, image side is at the rightmost position);

[0040] Figure 6 Aberration diagrams of the wide working distance high-performance line scan lens provided in Example 3;

[0041] Wherein, 1-first lens group G1; 2-second lens group G2; 3-image plane IMA; 4-front lens group GF; 5-rear lens group GB; 6-aperture stop ST; 7-first optical element; 8-second optical element; 9-optical element L 21 ;10-Optical Element L 22 ; 11-Third optical element; 12-Fourth optical element; 13-Fifth optical element; 14-Sixth optical element; 15-Seventh optical element; 16-Eighth optical element; 17-Ninth optical element; 18-Tenth optical element. Detailed Implementation

[0042] It should be noted that the use of terms such as "first", "second", "third", "fourth", "fifth", "sixth", "seventh", "eighth", "ninth" and "tenth" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0043] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0044] It is understood that the present invention achieves its objectives through some embodiments.

[0045] Example 1

[0046] like Figure 1As shown, this invention provides a high-performance line scan lens with a wide working distance. From the object side to the image side, a first lens group G11, a second lens group G22, and an image plane IMA3 are arranged sequentially. During focusing, both the first lens group G11 and the second lens group G22 move along the optical axis. Focusing of the lens can be achieved by changing the distance between the first lens group G11 and the second lens group G22. During focusing, the movement of both the first lens group G11 and the second lens group G22 along the optical axis allows the lens to simultaneously focus by changing the distance between the first lens group G11 and the second lens group G22, thereby changing the lateral magnification of the second lens group G22, compensating for the image plane offset, and meeting the requirement of high-quality imaging at a wide working distance. The first lens group G11 includes a front lens group GF4, an aperture stop ST6, and a rear lens group GB5 arranged sequentially from the object plane to the image plane. During focusing, the front lens group GF4, the aperture stop ST6, and the rear lens group GB5 move synchronously along the optical axis. The front lens group GF4 includes a first optical element 7 and a second optical element 8 arranged sequentially from the object plane to the image plane, and the second optical element 8 is a cemented lens group. The rear lens group GB5 includes a sixth optical element 14, a seventh optical element 15, an eighth optical element 16, a ninth optical element 17, and a tenth optical element 18 arranged sequentially from the object plane to the image plane, and the seventh optical element 15 and the eighth optical element 16 are both cemented lens groups. The optical parameters of a wide working distance high-performance line scan lens provided in Embodiment 1 are shown in Table 1 below:

[0047] Table 1. Optical parameters of the wide working distance high-performance line scan lens provided in Example 1.

[0048] 0 D(0) 1 L1 30.750 2.1 1.8593 31.78 2 52.586 1.6 3 L2 -43.206 0.9 1.6769 30.68 4 L3 14.293 4.9 1.8575 27.79 5 -59.402 0.5 6 Stop INF 1.2 7 L4 53.157 1.2 1.4933 63.09 8 23.298 0.7 9 L5 45.995 4.1 1.59559 67.33 10 L6 -14.141 0.7 1.85728 27.39 11 L7 14.690 3.6 1.75305 52.64 12 -252.325 0.7 13 L8 39.804 5.5 1.85506 23.79 14 L9 -20.510 0.9 1.58536 39.14 15 28.093 3.0 16 L10 -33.597 2.4 1.75844 52.33 17 -23.405 2.0 18 L11 -14.216 1.2 1.45771 90.27 19 -70.064 D(1) 20 L12 -116.144 5.3 1.75844 52.33 21 L13 -21.895 1.4 1.65432 32.21 22 -39.50 D(2) 1 0 23 Cover INF 1.0 1.51872 64.21 24 IMG INF 0

[0049] In Table 1, in the column containing surface number Si, 0 represents the object plane, 24 (IMG) represents the image plane IMG, and surface numbers 1-23 are the surfaces of each lens and aperture stop from the object plane to the image plane, respectively. It should be noted that the cemented surfaces of different lenses in a cemented lens group are represented as the same surface.

[0050] The focusing data for this embodiment is referenced in Table 2 below:

[0051] Table 2. Focusing data for the wide working distance high-performance line scan lens provided in Example 1.

[0052]

[0053] In Table 1, RED is the magnification, WD is the standard working distance, Far is the farthest working distance, and Near is the closest working distance.

[0054] The second lens group in this embodiment Where, β Fβ is the lateral magnification of the second lens group G22 at its farthest working distance. N The second lens group G22 has the following lateral magnification at its closest working distance: This conditional expression specifies the range of the ratio between the lateral magnification of the second lens group G22 and the difference between 1 at the farthest and closest working distances. By reasonably selecting the lateral magnification of the second lens group G22, the lens can maintain good imaging performance within a certain working distance and achieve high-quality imaging at a wide working distance.

[0055] The second lens group in this embodiment Where f1 is the focal length of the first lens group G11 and f2 is the focal length of the second lens group G22; the second lens group G22 satisfies the conditional expression This conditional expression specifies the range of the ratio between the focal lengths of the second lens group G22 and the first lens group G11, which enables the line scan lens to have a large target surface while meeting the requirements of miniaturization.

[0056] In this embodiment, the first lens group G11 Where f is the focal length of the line scan lens, and f1 is the focal length of the first lens group G11; the first lens group G11 satisfies 0.69 ≤ This conditional expression specifies the range of the ratio between the square of the focal length of the entire lens group and the first lens group G11, which enables the line scan lens to have a wide working distance while having a small adjustment interval, thus meeting the requirements of high-precision focusing.

[0057] In this embodiment, the second lens group G22 consists of optical elements L with positive optical power arranged sequentially from the object side. 21 9 and optical element L with negative optical power 22 The cemented lens consists of 10 elements, the second lens group Where, n 21 and n 22 The optical elements L are respectively represented by 21 The d-line refractive index of 9 and the optical element L 22 d-line refractive index of 10; υ 21 and υ 22 The optical elements L are respectively represented by 21 The Abbe number of 9 and the optical element L 22 With an Abbe number of 10, the second lens group G22 satisfies the following condition: ≥35; By reasonably setting the refractive index and Abbe number of the glass material with positive and negative optical power in the cemented lens of the second lens group G22, the positional chromatic aberration and magnification chromatic aberration of the optical system are controlled within a certain range, so as to achieve high-quality imaging while meeting the wide working distance requirement;

[0058] The wide working distance high-performance line scan lens provided in this embodiment The wide working distance high-performance line scan lens meets the following conditions This conditional expression specifies the range of the ratio between the total optical length at the farthest working distance and the total optical length at the closest working distance. It can effectively control the variation of the total optical length of the line scan lens to meet the requirements of high-performance imaging while satisfying wide working distance imaging. By controlling the total optical length at different working distances, the miniaturization of the line scan lens can be achieved while realizing wide working distance imaging.

[0059] like Figure 2 As shown in the diagram, the aberration maps of the wide working distance high-performance line scan lens provided in this embodiment show that spherical aberration is controlled within 0.1mm, astigmatism and field curvature are controlled within 0.1mm, and optical distortion is less than 1%, meeting the parameter requirements of a wide working distance high-performance line scan lens. While meeting the wide working distance requirement, this lens also features low distortion and high resolution, meeting the requirements of high-pixel, large-area photosensitive sensors. In different field-of-view detection applications, this lens can simultaneously take into account the needs of optical distortion, field of view, and working conditions, meeting the requirements of high-performance imaging.

[0060] Example 2

[0061] like Figure 3 As shown, this invention provides a wide working distance high-performance line scan lens. From the object side to the image side, a first lens group G11, a second lens group G22, and an image plane IMA3 are sequentially arranged. During focusing, both the first lens group G11 and the second lens group G22 move along the optical axis. Focusing is achieved by changing the distance between the first lens group G11 and the second lens group G22. During focusing, the movement of both the first lens group G11 and the second lens group G22 along the optical axis allows the lens to simultaneously adjust the lateral magnification of the second lens group G22 through changes in the distance between the first lens group G11 and the second lens group G22, compensating for the image plane offset. The current requirement is for high-quality imaging at a wide working distance; the first lens group G11 includes a front lens group GF4, an aperture stop ST6, and a rear lens group GB5 arranged sequentially from the object plane to the image plane. During focusing, the front lens group GF4, the aperture stop ST6, and the rear lens group GB5 move synchronously along the optical axis; the front lens group GF4 includes a first optical element 7, a second optical element 8, a third optical element 11, a fourth optical element 12, and a fifth optical element 13 arranged sequentially from the object plane to the image plane, and the third optical element 11 is a cemented lens group; the rear lens group GB5 includes a sixth optical element 14, and the sixth optical element 14 is a cemented lens group; Embodiment 2 provides the optical parameters of a high-performance line scan lens with a wide working distance as shown in Table 3 below:

[0062] Table 3 shows the optical parameters of a wide working distance, high-performance line scan lens provided in Example 2.

[0063] 0 (D0) 1 L12 30.38 4.5 1.9251 18.43 2 21.82 1.9 3 L2 31.95 5.8 1.8988 33.03 4 77.51 2.0 5 L3 -100.02 7.9 1.6257 57.19 6 L4 -27.23 0.8 1.7574 28.42 7 64.35 1.3 8 L5 46.74 3.3 1.9583 17.94 9 -114.80 0.2 10 L6 33.93 0.8 1.93644 21.41 11 21.39 6.0 12 Stop INF 4.0 13 L7 47.23 6.0 1.73492 53.73 14 L8 -19.82 3.1 1.5997 40.9 15 39.56 D(1) 16 L9 -415.24 3.2 1.88834 39.22 17 L10 -35.14 0.8 1.55468 38.59 18 INF D(2) 19 Cover INF 0.8 1.51872 64.21 20 IMG INF 0

[0064] In Table 3 above, in the column containing surface number Si, 0 represents the object plane, 20 (IMG) represents the image plane IMG, and surface numbers 1-19 are the surfaces of each lens and aperture stop from the object plane to the image plane, respectively. It should be noted that the cemented surfaces of different lenses in a cemented lens group are represented as the same surface. The focusing data for this embodiment is referenced in Table 4 below:

[0065] Table 4. Focusing data for the wide working distance high-performance line scan lens provided in Example 2.

[0066]

[0067]

[0068] In Table 4, RED is the magnification, WD is the standard working distance, Far is the farthest working distance, and Near is the closest working distance.

[0069] The second lens group in this embodiment Where, β F β is the lateral magnification of the second lens group G22 at its farthest working distance. N The second lens group G22 has the following lateral magnification at its closest working distance: This conditional expression specifies the range of the ratio between the lateral magnification of the second lens group G22 and the difference between 1 at the farthest and closest working distances. By reasonably selecting the lateral magnification of the second lens group G22, the lens can maintain good imaging performance within a certain working distance and achieve high-quality imaging at a wide working distance.

[0070] The second lens group in this embodiment Where f1 is the focal length of the first lens group G11 and f2 is the focal length of the second lens group G22; the second lens group G22 satisfies the conditional expression This conditional expression specifies the range of the ratio between the focal lengths of the second lens group G22 and the first lens group G11, which enables the line scan lens to have a large target surface while meeting the requirements of miniaturization.

[0071] In this embodiment, the first lens group Where f is the focal length of the line scan lens, and f1 is the focal length of the first lens group G11; the first lens group G11 satisfies This conditional expression specifies the range of the ratio between the square of the focal length of the entire lens group and the first lens group G11, which enables the line scan lens to have a wide working distance while having a small adjustment interval, thus meeting the requirements of high-precision focusing.

[0072] This embodiment provides optical elements L with positive optical power arranged sequentially from the object side in the second lens group G22. 21 9 and optical element L with negative optical power 22 A cemented lens consisting of 10 elements, the second lens group G22 Where, n 21 and n 22 The optical elements L are respectively represented by 21 9 and the optical element L 22 d-line refractive index of 10; υ 21 and υ 22 The optical elements L are respectively represented by 21 9 and the optical element L 22 With an Abbe number of 10, the second lens group G22 satisfies the following condition: By reasonably setting the refractive index and Abbe number of the glass material with positive and negative optical power in the cemented lens of the second lens group G22, the positional chromatic aberration and magnification chromatic aberration of the optical system are controlled within a certain range, achieving high-quality imaging while meeting the wide working distance requirement.

[0073] The wide working distance high-performance line scan lens The wide working distance high-performance line scan lens meets the following conditions This conditional expression specifies the range of the ratio between the total optical length at the farthest working distance and the total optical length at the closest working distance. It can effectively control the change in the total optical length of the line scan lens to meet the requirements of high-performance imaging while satisfying wide working distance imaging. By controlling the total optical length at different working distances, the miniaturization of the line scan lens can be achieved while realizing wide working distance imaging.

[0074] like Figure 4 As shown in the diagram, the aberration maps of the wide working distance high-performance line scan lens provided in this embodiment show that spherical aberration is controlled within 0.1mm, astigmatism and field curvature are controlled within 0.1mm, and optical distortion is less than 1%, meeting the parameter requirements of a wide working distance high-performance line scan lens. While meeting the wide working distance requirement, this lens also features low distortion and high resolution, meeting the requirements of high-pixel, large-area photosensitive sensors. In different field-of-view detection applications, this lens can simultaneously take into account the needs of optical distortion, field of view, and working conditions, meeting the requirements of high-performance imaging.

[0075] Example 3

[0076] like Figure 5As shown, this invention provides a high-performance line scan lens with a wide working distance. From the object side to the image side, a first lens group G11, a second lens group G22, and an image plane IMA3 are arranged sequentially. During focusing, both the first lens group G11 and the second lens group G22 move along the optical axis. Focusing of the lens can be achieved by changing the distance between the first lens group G11 and the second lens group G22. During focusing, the movement of both the first lens group G11 and the second lens group G22 along the optical axis allows the lens to simultaneously focus by changing the distance between the first lens group G11 and the second lens group G22, thereby changing the lateral magnification of the second lens group G22, compensating for the image plane offset, and meeting the requirement of high-quality imaging at a wide working distance. The first lens group G11 includes a front lens group GF4, an aperture stop ST6, and a rear lens group GB5 arranged sequentially from the object plane to the image plane. During focusing, the front lens group GF4, the aperture stop ST6, and the rear lens group GB5 move synchronously along the optical axis. The front lens group GF4 includes a first optical element 7, a second optical element 8, a third optical element 11, a fourth optical element 12, and a fifth optical element 13 arranged sequentially from the object plane to the image plane. The rear lens group GB5 includes a sixth optical element 14, a seventh optical element 15, an eighth optical element 16, a ninth optical element 17, and a tenth optical element 18 arranged sequentially from the object plane to the image plane. The sixth optical element 14 is a cemented lens group. The optical parameters of a wide working distance high-performance line scan lens provided in Embodiment 3 are shown in Table 5 below.

[0077] Table 5 shows the optical parameters of a wide working distance, high-performance line scan lens provided in Example 3.

[0078]

[0079]

[0080] In Table 5 above, in the column containing surface number Si, 0 represents the object plane, 27 (IMG) represents the image plane IMG, and surface numbers 1-26 are the surfaces of each lens and aperture stop from the object plane to the image plane, respectively. It should be noted that the cemented surfaces of different lenses in a cemented lens group are represented as the same surface; the focusing data for this embodiment is referenced in Table 6 below:

[0081] Table 6. Focusing data for the wide working distance high-performance line scan lens provided in Example 3.

[0082]

[0083] In Table 6 above, RED is the magnification, WD is the standard working distance, Far is the farthest working distance, and Near is the closest working distance.

[0084] The second lens group in this embodiment Where, βF β is the lateral magnification of the second lens group G22 at its farthest working distance. N The second lens group G22 has the following lateral magnification at its closest working distance: This conditional expression specifies the range of the ratio between the lateral magnification of the second lens group G22 and the difference between 1 at the farthest and closest working distances. By reasonably selecting the lateral magnification of the second lens group G22, the lens can maintain good imaging performance within a certain working distance and achieve high-quality imaging at a wide working distance.

[0085] The second lens group in this embodiment Where f1 is the focal length of the first lens group G11 and f2 is the focal length of the second lens group G22; the second lens group G22 satisfies the conditional expression This conditional expression specifies the range of the ratio between the focal lengths of the second lens group G22 and the first lens group G11, which enables the line scan lens to have a large target surface while meeting the requirements of miniaturization.

[0086] In this embodiment, the first lens group Where f is the focal length of the line scan lens, and f1 is the focal length of the first lens group G11; the first lens group G11 satisfies This conditional expression specifies the range of the ratio between the square of the focal length of the entire lens group and the first lens group G11, which enables the line scan lens to have a wide working distance while having a small adjustment interval, thus meeting the requirements of high-precision focusing.

[0087] The second lens group G22 consists of optical elements L with positive optical power arranged sequentially from the object side. 21 9 and optical element L with negative optical power 22 The cemented lens consists of 10 elements, the second lens group Where, n 21 and n 22 The optical elements L are respectively represented by 21 9 and the optical element L 22 d-line refractive index of 10; υ 21 and υ 22 The optical elements L are respectively represented by 21 9 and the optical element L 22 With an Abbe number of 10, the second lens group G22 satisfies the following condition: n 21 -n 22 ≥0.10; By reasonably setting the refractive index and Abbe number of the glass material with positive and negative optical power in the cemented lens of the second lens group G22, the positional chromatic aberration and magnification chromatic aberration of the optical system are controlled within a certain range, achieving high-quality imaging while meeting the wide working distance requirement.

[0088] The wide working distance high-performance line scan lens The wide working distance high-performance line scan lens meets the following conditions This conditional expression specifies the range of the ratio between the total optical length at the farthest working distance and the total optical length at the closest working distance. It can effectively control the variation of the total optical length of the line scan lens to meet the requirements of high-performance imaging while satisfying wide working distance imaging. By controlling the total optical length at different working distances, the miniaturization of the line scan lens can be achieved while realizing wide working distance imaging.

[0089] like Figure 6 As shown in the diagram, the aberration maps of the wide working distance high-performance line scan lens provided in this embodiment show that spherical aberration is controlled within 0.1mm, astigmatism and field curvature are controlled within 0.1mm, and optical distortion is less than 2%, meeting the parameter requirements of a wide working distance high-performance line scan lens. While meeting the wide working distance requirement, this lens also features low distortion and high resolution, meeting the requirements of high-pixel, large-area photosensitive sensors. In different field-of-view detection applications, this lens can simultaneously take into account the needs of optical distortion, field of view, and working conditions, meeting the requirements of high-performance imaging.

[0090] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by the present invention.

Claims

1. A wide working distance, high-performance line scan lens, characterized in that, It consists of a first lens group G1 and a second lens group G2 arranged sequentially from the object side to the image side. During the focusing process, both the first lens group G1 and the second lens group G2 move along the optical axis. The lens can be focused by changing the interval between the first lens group G1 and the second lens group G2. The second lens group G2 satisfies the following condition: ； Where f1 is the focal length of the first lens group G1 and f2 is the focal length of the second lens group G2; The second lens group G2 satisfies the following condition: ； where β F is the lateral magnification of the second lens group G2 at the farthest working distance, and β N is the lateral magnification of the second lens group G2 at the closest working distance.

2. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The first lens group G1 satisfies the following condition: ； Where f is the focal length of the line scan lens, and f1 is the focal length of the first lens group G1.

3. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The second lens group G2 is sequentially arranged from the object side an optical element L having positive refractive power 21 and an optical element L having negative refractive power 22 The resulting cemented lens satisfies the following conditional expression: ； ； wherein n 21 and n 22 respectively denote the d-line refractive index of the optical element L 21 and the d-line refractive index of the optical element L 22 ; υ 21 and υ 22 respectively denote the Abbe number of the optical element L 21 and the Abbe number of the optical element L 22 .

4. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The wide working distance high-performance line scan lens satisfies the following condition: ； TTL F is the total optical length of the line scan lens at the farthest working distance, TTL N is the total optical length of the line scan lens at the nearest working distance.

5. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The first lens group G1 includes a front lens group GF, an aperture stop ST, and a rear lens group GB arranged sequentially from the object plane to the image plane. During focusing, the front lens group GF, the aperture stop ST, and the rear lens group GB move synchronously along the optical axis.

6. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The front lens group GF includes a first optical element and a second optical element arranged sequentially from the object plane to the image plane, wherein the second optical element is a cemented lens group.

7. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The front lens group GF includes a first optical element, a second optical element, a third optical element, a fourth optical element and a fifth optical element arranged sequentially from the object plane to the image plane, wherein the third optical element is a cemented lens group.

8. The wide working distance high-performance line scan lens according to claim 1, characterized in that, The second lens group G2 has an image plane IMA on the side near the image side.

Images