A machine vision lens with large target area and wide viewing angle

Abstract

The present invention discloses a machine vision lens with a large target surface and a large viewing angle, comprising a first lens group G1, a second lens group G2 and a third lens group G3 with positive optical power arranged in sequence from the object surface to the image surface. When focusing, the first lens group G1 and the third lens group G3 are fixed relative to the image surface, and the second lens group G2 moves along the optical axis. The lens can achieve high-quality imaging in a wide working distance range by reasonably controlling the focal length ratio, lens shape and optical power of each lens group, with small distortion and high resolution, and has a large target surface, a large viewing angle, and high pixel performance, and is easy to achieve small and light weight of the lens.

Description

Technical Field

[0001] The invention belongs to the technical field of lenses, and in particular relates to a machine vision lens with a large target surface and a large viewing angle. Background Art

[0002] Machine vision refers to the use of machines to replace human eyes for measurement and judgment. The visual lens captures the picture, and the captured target is converted into image signals through image capture devices such as industrial cameras. Then, the image processing system calculates these signals and extracts target features such as position, size, appearance, etc., and then outputs the results according to preset conditions to achieve automatic recognition, judgment, measurement and other functions.

[0003] Existing machine vision lenses generally have defects of different types or degrees, such as small target surface, low pixel, small field of view, large distortion, etc. Therefore, with the development of chip technology and the improvement of detection level, the research and development of machine vision lenses with small size, large target surface, large viewing angle, high pixel and low distortion is more urgent. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned problems and to propose a machine vision lens with a large target area and a large viewing angle, which has small distortion and high resolution at various working distances and meets the requirements of a large target area, a large viewing angle and a high pixel.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a large-image-surface and large-angle machine vision lens, comprising a first lens group G arranged in sequence from the object plane to the image plane. 1 , the second lens group G 2 and the third lens group G having positive refractive power 3 , when focusing, the first lens group G 1 And the third lens group G 3 The second lens group G is fixed relative to the image plane. 2 Move along the optical axis;

[0007] The large-area and large-angle machine vision lens also meets the following conditions:

[0008]

[0009]

[0010] Among them, f 1 The first lens group G 1 The focal length, f 2 The second lens group G 2 The focal length, f 12 The first lens group G 1 and the second lens group G 2The composite focal length is f, and f is the focal length of the optical system.

[0011] Preferably, the first lens group G 1 The optical element L having positive optical power is arranged in sequence from the object plane to the image plane. 11 , an optical element L having negative optical power 12 , an optical element L having negative optical power 13 , an optical element L having negative optical power 14 and an optical element L having negative optical power 15 , and the following conditions are met:

[0012]

[0013] Among them, f a is the optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The synthetic focal length.

[0014] Preferably, the first lens group G 1 It also includes optical elements L arranged in sequence from the object plane to the image plane 16 and optical element L 17 , optical element L 16 Located in the optical element L 15 The image side of the optical element L is a cemented lens group. 17 It is a single lens.

[0015] Preferably, the first lens group G 1 Also included is the optical element L 17 Optical element L on the image side 18 , optical element L 18 It is a single lens.

[0016] Preferably, the optical element L 11 It is a meniscus lens with the convex surface facing the object plane and meets the following conditions:

[0017]

[0018] Among them, TTL is the total optical length of the machine vision lens, and D is the optical element L 11 is the maximum effective radius, and θ is the half field of view angle of the machine vision lens.

[0019] Preferably, the optical element L 11 The following conditions are also met:

[0020] n d1 ≤1.80

[0021] v d1 ≥43

[0022] Among them, n d1 is the optical element L 11 The d-line refractive index, v d1 is the optical element L 11 The Abbe number of .

[0023] Preferably, the optical element L 12 、Optical element L 13 and optical element L 14 All are meniscus lenses with the convex surface facing the object plane and meet the following conditions:

[0024] (n d2 +n d3 +n d4 ) / 3≥1.9

[0025] Among them, n d2 is the optical element L 12 The d-line refractive index, n d3 is the optical element L 13 The d-line refractive index, n d4 is the optical element L 14 The d-line refractive index.

[0026] Preferably, the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , optical element L 21 is a single lens, optical element L 22 It is a single lens or a cemented lens group.

[0027] Preferably, the third lens group G 3 Including optical element L 31 , optical element L 31 It is a cemented lens group and meets the following conditions:

[0028]

[0029] Among them, f 31 is the optical element L 31 The focal length, f 3 The third lens group G 3 focal length.

[0030] Preferably, the large-image-area and large-angle machine vision lens further includes a stop ST, which is located in the first lens group G. 1 and the second lens group G 2 between.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1) By controlling the first lens group G 1 The ratio range between the focal length of the optical system and the first lens group G 1 and the second lens group G 2 The ratio range between the synthetic focal length and the focal length of the optical system and the reasonable selection of the magnification of the focusing group can achieve high-quality imaging within a certain working distance range; at the same time, by reasonably controlling the second lens group G 2 The ratio range between the focal length of the optical system ensures that the aberrations change little within the entire working distance, and in addition to meeting the characteristics of the optical system such as high pixels, large target surface, small distortion, and large field of view, high-quality imaging is achieved.

[0033] 2) By properly configuring the first lens group G 1 The focal power and lens shape of the five optical elements close to the object side, as well as the ratio range between the synthetic focal length of the five optical elements and the focal length of the optical system, not only achieve a large field of view of more than 98° on a large 1.2-inch target surface, but also meet the requirements of low distortion of industrial lenses. At the same time, by reasonably selecting the refractive index and Abbe number of the material, the position chromatic aberration and spherical aberration of the optical system are controlled within the specified range, achieving high-quality imaging while meeting the large field of view.

[0034] 3) By controlling the first lens group G 1 The lens shape of the Zhongshou lens can effectively shorten the total optical length, achieving large target area and large field of view while making the machine vision lens small and lightweight;

[0035] 4) By defining the third lens group G 3 The first optical element close to the object plane is a cemented lens group, which can correct chromatic aberration during focusing and achieve high-quality imaging while meeting a wide working distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the overall structure of the lens of Embodiment 1 of the present invention;

[0037] Figure 2 Graphs of spherical aberration, astigmatism and distortion when the working distance is 300 mm in Example 1 of the present invention;

[0038] Figure 3 This is the MFT diagram of Example 1 of the present invention when the working distance is 300 mm;

[0039] Figure 4 This is the MFT diagram of Example 1 of the present invention when the working distance is 600 mm;

[0040] Figure 5This is the MFT diagram of Example 1 of the present invention when the working distance is 100 mm;

[0041] Figure 6 Schematic diagram of the overall structure of a lens according to Embodiment 2 of the present invention;

[0042] Figure 7 Graphs of spherical aberration, astigmatism and distortion when the working distance is 300 mm in Example 2 of the present invention;

[0043] Figure 8 This is the MFT diagram of Example 2 of the present invention when the working distance is 300 mm;

[0044] Fig. 9 This is the MFT diagram of Example 2 of the present invention when the working distance is 600 mm;

[0045] Fig.10 This is the MFT diagram of Example 2 of the present invention when the working distance is 100 mm;

[0046] Fig.11 Schematic diagram of the overall structure of a lens according to Embodiment 3 of the present invention;

[0047] Fig.12 Graphs of spherical aberration, astigmatism and distortion when the working distance is 300 mm according to Example 3 of the present invention;

[0048] Fig.13 This is the MFT diagram of Example 3 of the present invention when the working distance is 300 mm;

[0049] Fig.14 This is the MFT diagram of Example 3 of the present invention when the working distance is 600 mm;

[0050] Fig.15 This is the MFT diagram of Example 3 of the present invention when the working distance is 100 mm;

[0051] Fig.16 Schematic diagram of the overall structure of a lens according to Embodiment 4 of the present invention;

[0052] Fig.17 Graphs of spherical aberration, astigmatism and distortion when the working distance is 300 mm according to Example 4 of the present invention;

[0053] Fig.18 This is the MFT diagram of Example 4 of the present invention when the working distance is 300 mm;

[0054] Fig.19 This is the MFT diagram of Example 4 of the present invention when the working distance is 600 mm;

[0055] Fig. 20 This is the MFT diagram of Example 4 of the present invention when the working distance is 100 mm. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] The relevant symbols in this application specification are defined as follows: 1 The first lens group G 1 The focal length, f 2 The second lens group G 2 The focal length, f 3 The third lens group G 3 The focal length, f 12 The first lens group G 1 and the second lens group G 2 The composite focal length of the optical system is f, and f a is the optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The composite focal length, f 31 is the optical element L 31 The focal length of the machine vision lens, TTL is the total optical length of the machine vision lens, and D is the optical element L 11 The maximum effective radius of the machine vision lens is θ, and S is the half field of view of the machine vision lens. i is the surface number; R i is the radius of curvature; d i is the on-axis surface distance between the ith surface and the i+1th surface, n d1 is the optical element L 11 The d-line refractive index, v d1 is the optical element L 11 The Abbe number, n d2 is the optical element L 12 The d-line refractive index, n d3 is the optical element L 13 The d-line refractive index, n d4 is the optical element L 14 The d-line refractive index, n d is the refractive index, ν d is the Abbe number, Fno is the F number, RED is the magnification; D(0) is the working distance, i.e., the distance from the object plane to the optical element L 11 The axial distance between the vertices of the side surfaces of the object plane, D(1) is the distance between the first lens group G 1 With the second lens group G 2The axial distance between adjacent face vertices of the second lens group G 2 With the third lens group G 3 The on-axis distance between adjacent face vertices of , ∞ indicates that the surface is flat. In the lens-related parameter data, the length unit is mm, and the unit will be omitted below.

[0058] It should be noted that the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0059] A machine vision lens with a large target surface and a large viewing angle comprises a first lens group G arranged in sequence from the object surface to the image surface 1 , the second lens group G 2 and the third lens group G having positive refractive power 3 , when focusing, the first lens group G 1 And the third lens group G 3 The second lens group G is fixed relative to the image plane. 2 Move along the optical axis;

[0060] The large-area and large-angle machine vision lens also meets the following conditions:

[0061]

[0062]

[0063] Among them, f 1 The first lens group G 1 The focal length, f 2 The second lens group G 2 The focal length, f 12 The first lens group G 1 and the second lens group G 2 The composite focal length is f, and f is the focal length of the optical system.

[0064] The machine vision lens of the present application includes a first lens group G arranged in sequence from the object plane to the image plane. 1 , the second lens group G 2 and the third lens group G having positive refractive power 3 , the second lens group G 2 Movable focus adjustment. This lens can achieve high-quality imaging while achieving a large field of view, meeting the requirements of large target surface and high pixel. Among them, conditional formula (1) stipulates that the first lens group G 1The ratio range between the focal length of the optical system and the first lens group G 1 and the second lens group G 2 The ratio range between the synthetic focal length and the focal length of the optical system is as follows. The range of the conditional expression (1) helps to reasonably select the focusing group, i.e., the second lens group G. 2 If the condition (1) is exceeded, the second lens group G 2 As the focusing group, the magnification is too high, which causes the image plane to move too much during the focusing process. The distortion, field curvature and other aberrations introduced cannot be corrected by the third lens group G. 3 Correction, resulting in a decrease in image quality. Condition (2) stipulates that the second lens group G 2 The range of the ratio between the optical system focal length and the optical system focal length. The range of the conditional expression (2) helps to reasonably select the second lens group G. 2 If the range of condition (2) is exceeded, the second lens group G 2 The focal length of the lens is too large, and the spherical aberration, coma and other aberrations are too large, so the lens cannot pass through the third lens group G. 3 Correction results in a decrease in image quality.

[0065] In one embodiment, the first lens group G 1 The optical element L having positive optical power is arranged in sequence from the object plane to the image plane. 11 , an optical element L having negative optical power 12 , an optical element L having negative optical power 13 , an optical element L having negative optical power 14 and an optical element L having negative optical power 15 , and the following conditions are met:

[0066]

[0067] Among them, f a is the optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The synthetic focal length.

[0068] Among them, the first lens group G 1 Optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15When the optical powers are set to positive, negative, negative, negative, and negative in sequence, the machine vision lens can have a large target surface and a large field of view of more than 98°. Among them, conditional formula (3) stipulates that the first lens group G 1 The ratio of the combined focal length of the five optical elements close to the object side to the focal length of the optical system is within the range. If the upper limit of conditional expression (3) is exceeded, the optical element L of the first lens group 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The synthesized focal length is too small to form a reverse telephoto structure and achieve wide field of view imaging. 1 Optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The synthesized focal length is too large, and the spherical aberration, coma and other aberrations are too large, which cannot be corrected by other lens groups, resulting in a decrease in imaging performance. When the machine vision lens meets the condition (3), a large field of view can be obtained while ensuring good imaging quality.

[0069] In one embodiment, the first lens group G 1 It also includes optical elements L arranged in sequence from the object plane to the image plane 16 and optical element L 17 , optical element L 16 Located in the optical element L 15 The image side of the optical element L is a cemented lens group. 17 It is a single lens.

[0070] Among them, by properly controlling the optical element L 16 and optical element L 17 The optical focal length of the first lens group G1 is adjusted to achieve an appropriate magnification, while correcting various aberrations in the first lens group G1, thereby reducing the need for aberration correction of the second lens group G2 and the third lens group G3.

[0071] In one embodiment, the first lens group G 1 Also included is the optical element L 17 Optical element L on the image side 18 , optical element L 18 It is a single lens.

[0072] Among them, through the optical element L 18 It is possible to further achieve coordination of different optical powers, adjust the magnification of the first lens group G1, and further correct various aberrations to achieve complete correction of aberrations within the group.

[0073] It should be noted that, in order to achieve a better intra-group aberration correction effect, the first lens group G is 1 Optical element L 15 Any number of optical elements can be arranged on the image side of the optical element L, and the optical element can be a single lens or a cemented lens group. 18 Other optical elements are added on the image side.

[0074] In one embodiment, the optical element L 11 It is a meniscus lens with the convex surface facing the object plane and meets the following conditions:

[0075]

[0076] Among them, TTL is the total optical length of the machine vision lens, and D is the optical element L 11 is the maximum effective radius, and θ is the half field of view angle of the machine vision lens.

[0077] Among them, by controlling the first lens group G 1 The first lens is the optical element L 11 The lens shape can effectively shorten the total optical length, and achieve the miniaturization of the machine vision lens while realizing large target surface imaging. Conditional formula (4) stipulates the ratio range between the total optical length of the machine vision lens, the optical aperture of the first lens, and the field of view of the machine vision lens, which can effectively shorten the total optical length of the lens, reduce the weight, and meet the requirements of a large field of view.

[0078] In one embodiment, the optical element L 11 The following conditions are also met:

[0079] n d1 ≤1.80 (5)

[0080] v d1 ≥43 (6)

[0081] Among them, n d1 is the optical element L 11 The d-line refractive index, v d1 is the optical element L 11 The Abbe number of the first lens group G is set appropriately. 1 The first lens is the optical element L 11 Refractive index and Abbe number of the material, preferably the optical element L 11The optical system is made of glass material, and the position chromatic aberration and spherical aberration of the optical system are controlled within the specified range, so as to achieve high-quality imaging while satisfying a wide field of view. If the upper limit of conditional expression (5) is exceeded, the focal length of the positive lens is too large, and the spherical aberration moves in the negative direction, resulting in excessive correction of the spherical aberration and poor center imaging performance. If the lower limit of conditional expression (6) is exceeded, the dispersion of the positive lens material is too large, resulting in insufficient correction of the position chromatic aberration and poor center imaging performance.

[0082] In one embodiment, the optical element L 12 、Optical element L 13 and optical element L 14 All are meniscus lenses with the convex surface facing the object plane and meet the following conditions:

[0083] (n d2 +n d3 +n d4 ) / 3≥1.9 (7)

[0084] Among them, n d2 is the optical element L 12 The d-line refractive index, n d3 is the optical element L 13 The d-line refractive index, n d4 is the optical element L 14 The d-line refractive index.

[0085] Among them, by controlling the first lens group G 1 The optical element L 12 、Optical element L 13 and optical element L 14 shape, achieving the imaging requirements of large field of view and large target surface. And conditional formula (7) further stipulates that the optical element L 12 、Optical element L 13 and optical element L 14 The average refractive index of the three materials is preferably the optical element L 12 、Optical element L 13 and optical element L 14 For glass materials, if the lower limit of conditional expression (7) is exceeded, the refractive index is too low, the optical power of the optical element is insufficient, and the imaging requirements of a large field of view cannot be met.

[0086] In one embodiment, the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , optical element L 21 is a single lens, optical element L 22 It is a single lens or a cemented lens group.

[0087] Among them, when the lens is focusing, the second lens group G 2 The setting can ensure that the image plane and the working distance change in a consistent manner. It should be noted that the second lens group G 2 It can also be used in optical element L 22 Several optical elements are added in sequence on the image side of the lens, and the optical elements can be single lenses or cemented lens groups. Through the coordination of the optical elements, different optical powers can be coordinated, and the magnification can be adjusted and the second lens group G can be corrected. 2 Internal aberrations.

[0088] In one embodiment, the third lens group G 3 Including optical element L 31 , optical element L 31 It is a cemented lens group and meets the following conditions:

[0089]

[0090] Among them, f 31 is the optical element L 31 The focal length, f 3 The third lens group G 3 focal length.

[0091] In which, by defining the optical element L 31 That is, the third lens group G 3 The first optical element close to the object plane is a cemented lens group, which can achieve chromatic aberration correction during focusing and achieve high-quality imaging while meeting a wide working distance. And conditional equation (8) further stipulates that the third lens group G 3 The first lens is the optical element L 31 With the third lens group G 3 If the upper limit of conditional expression (8) is exceeded, the optical element L 31 The excessive focal length of the third lens group G 3 The total length is too long. If it exceeds the lower limit of conditional expression (8), the optical element L 31 If the focal length is too small, it cannot provide sufficient chromatic aberration correction and cannot meet the high-performance imaging requirements of large target surfaces. Keeping it within this range will help improve imaging quality while achieving miniaturization.

[0092] It should be noted that, in order to achieve the coordination of different optical powers, the third lens group G is 3 Optical element L 31 Any number of optical elements may be disposed on the image plane side, and the optical element may be a single lens or a cemented lens group.

[0093] In one embodiment, the large-image-area and large-angle machine vision lens further includes a stop ST, which is located in the first lens group G. 1and the second lens group G 2 between.

[0094] Among them, by adjusting the light flux of the aperture ST, the stability of the relative illumination within different working distances is ensured, which is beneficial to improving the imaging quality. It should be noted that the position of the aperture ST can be fixed or follow the second lens group G. 2 Move or set between any optical elements in the lens as needed.

[0095] Hereinafter, embodiments of the large-target-area and large-angle machine vision lens of the present application will be described in detail based on the accompanying drawings.

[0096] Embodiment 1:

[0097] like Figure 1-5 As shown, a large-target-area and large-angle machine vision lens includes a first lens group G arranged in sequence from the object plane to the image plane 1 , aperture ST, second lens group G 2 , the third lens group G 3 Among them, the first lens group G 1 The optical elements L are arranged in sequence from the object plane to the image plane. 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 、Optical element L 15 、Optical element L 16 、Optical element L 17 and optical element L 18 , the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 、Optical element L 22 、Optical element L 23 、Optical element L 24 and optical element L 25 , the third lens group G 3 The optical elements L are arranged in sequence from the object plane to the image plane. 31 and optical element L 32

[0098] Specifically, Figure 1 As shown, L 11 is a positive meniscus lens, L 12 is a negative meniscus lens, L 13 is a negative meniscus lens, L 14 is a negative meniscus lens, L 15 is a double concave negative lens, L 16 It is a cemented lens group composed of a negative meniscus lens and a double convex lens arranged in sequence from the object plane to the image plane. 17 is a biconvex positive lens, L 18is a double concave negative lens; L 21 is a biconvex positive lens, L 22 is a negative meniscus lens, L 23 It is a cemented lens group composed of a double concave negative lens and a double convex positive lens arranged in sequence from the object plane to the image plane. 24 is a biconvex positive lens, L 25 is a negative meniscus lens; L 31 It is a cemented lens group composed of a positive meniscus lens and a negative meniscus lens arranged in sequence from the object plane to the image plane. 32 It is a double convex positive lens. Figure 1 The middle arrow indicates the second lens group G 2 The focusing group can be moved along the optical axis for focusing. 3 There is also an image plane protection glass CG in between.

[0099] The parameters of the lens of this embodiment satisfy: f = 8.0, Fno = 2.8, θ = 49.55°. The values ​​of each conditional expression are as follows:

[0100] Conditional Number (1) (2) (3) (4) (5) (6) (7) (8) Value 0.28 0.18 -1.88 5.03 1.79 47.52 1.959 -1.20

[0101] The optical data parameters of each lens of the lens are as follows:

[0102]

[0103]

[0104] In the above table, the surface number S i In this column, 0 represents the object plane, 36 (IMG) represents the image plane, and surface numbers 1 to 35 are the surfaces of each lens, aperture stop, and protective glass from the object plane to the image plane. It should be noted that the cemented surfaces of different lenses in the cemented lens group are represented as the same surface.

[0105] The focusing data parameters of this embodiment are as follows:

[0106] NO. I II III D(0) 300 600 100 RED 0.03 0.01 0.07 f 8.0 8.0 8.2 D(1) 3.03 3.39 1.82 D(2) 0.57 0.21 1.78

[0107] like Figure 2 As shown, the field of view of this embodiment reaches 99.1°, the spherical aberration in the aberration diagrams is controlled within 0.01mm, the astigmatism and field curvature are controlled within 0.05mm, and the optical distortion is less than 0.6%, meeting all the parameter requirements of machine vision lenses. Figure 3-5 As shown, when the working distances are 300mm, 100mm and 600mm respectively, the full image height MTF in the figure is >0.25@150lp / mm, which meets the imaging requirements of high pixels, large target surface and wide working distance, and has high imaging quality.

[0108] Embodiment 2:

[0109] like Figure 6-10 As shown, a large-target-area and large-angle machine vision lens includes a first lens group G arranged in sequence from the object plane to the image plane 1 , aperture ST, second lens group G 2 , the third lens group G 3 Among them, the first lens group G 1 The optical elements L are arranged in sequence from the object plane to the image plane. 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 、Optical element L 15 、Optical element L 16 、Optical element L 17 and optical element L 18 , the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , the third lens group G 3 The optical elements L are arranged in sequence from the object plane to the image plane. 31 、Optical element L 32 、Optical element L 33 、Optical element L 34 、Optical element L 35 and optical element L 36 .

[0110] Specifically, Figure 6 As shown, L 11 is a positive meniscus lens, L 12 is a negative meniscus lens, L 13 is a negative meniscus lens, L 14 is a negative meniscus lens, L 15 is a double concave negative lens, L 16 It is a cemented lens group composed of a negative meniscus lens and a double convex lens arranged in sequence from the object plane to the image plane. 17 is a biconvex positive lens, L 18 is a double concave negative lens; L 21 is a biconvex positive lens, L 22 is a negative meniscus lens; L 31 It is a cemented lens group composed of a negative meniscus lens and a double convex positive lens arranged in sequence from the object plane to the image plane. 32 is a biconvex positive lens, L 33 is a double concave negative lens, L 34 is a biconvex positive lens, L 35 is a negative meniscus lens, L 36 It is a double convex positive lens. Figure 6 The middle arrow indicates the second lens group G 2The focusing group can be moved along the optical axis for focusing. 3 There is also an image plane protection glass CG in between.

[0111] The parameters of the lens of this embodiment satisfy: f = 8.04, Fno = 2.8, θ = 49.72°. The values ​​of each conditional expression are as follows:

[0112] Conditional Number (1) (2) (3) (4) (5) (6) (7) (8) Value -0.18 0.26 -1.42 5.36 1.74 53.72 1.984 -4.64

[0113] The optical data parameters of each lens of the lens are as follows:

[0114]

[0115]

[0116] In the above table, the surface number S i In this column, 0 represents the object plane, 37 (IMG) represents the image plane, and surface numbers 1 to 36 are the surfaces of each lens, aperture stop, and protective glass from the object plane to the image plane. It should be noted that the cemented surfaces of different lenses in the cemented lens group are represented as the same surface.

[0117] The focusing data parameters of this embodiment are as follows:

[0118] NO. I II III D(0) 300 600 100 RED 0.03 0.01 0.06 f 8.04 8.12 7.78 D(1) 0.51 0.20 1.52 D(2) 1.20 1.52 0.20

[0119] like Figure 7 As shown, the field of view of this embodiment reaches 99.44°, the spherical aberration in the aberration diagrams is controlled within 0.01mm, the astigmatism and field curvature are controlled within 0.05mm, and the optical distortion is less than 0.6%, meeting all the parameter requirements of machine vision lenses. Figure 8-10 As shown, when the working distances are 300mm, 100mm and 600mm respectively, the full image height MTF in the figure is >0.25@150lp / mm, which meets the imaging requirements of high pixels, large target surface and wide working distance, and has high imaging quality.

[0120] Embodiment 3:

[0121] like Figure 11-15 As shown, a large-target-area and large-angle machine vision lens includes a first lens group G arranged in sequence from the object plane to the image plane 1 , aperture ST, second lens group G 2 , the third lens group G 3 Among them, the first lens group G 1 The optical elements L are arranged in sequence from the object plane to the image plane. 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 、Optical element L15 、Optical element L 16 and optical element L 17 , the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , the third lens group G 3 The optical elements L are arranged in sequence from the object plane to the image plane. 31 、Optical element L 32 、Optical element L 33 、Optical element L 34 and optical element L 35 .

[0122] Specifically, Fig.11 As shown, L 11 is a positive meniscus lens, L 12 is a negative meniscus lens, L 13 is a negative meniscus lens, L 14 is a negative meniscus lens, L 15 is a negative meniscus lens, L 16 It is a cemented lens group composed of a negative meniscus lens and a double convex lens arranged in sequence from the object plane to the image plane. 17 is a biconvex positive lens; L 21 is a double concave negative lens, L 22 It is a cemented lens group consisting of a double convex positive lens and a negative meniscus lens arranged in sequence from the object plane to the image plane; L 31 It is a cemented lens group composed of a double concave negative lens and a double convex positive lens arranged in sequence from the object plane to the image plane. 32 is a biconvex positive lens, L 33 is a double concave negative lens, L 34 It is a cemented lens group composed of a double convex positive lens and a negative meniscus lens arranged in sequence from the object plane to the image plane. 35 It is a double convex positive lens. Fig.11 The middle arrow indicates the second lens group G 2 The focusing group can be moved along the optical axis for focusing. 3 There is also an image plane protection glass CG in between.

[0123] The parameters of the lens of this embodiment satisfy: f = 8.05, Fno = 2.8, θ = 49.55°. The values ​​of each conditional expression are as follows:

[0124] Conditional Number (1) (2) (3) (4) (5) (6) (7) (8) Value -0.26 -0.12 -1.32 5.16 1.69 53.35 1.984 -3.58

[0125] The optical data parameters of each lens of the lens are as follows:

[0126]

[0127]

[0128] In the above table, the surface number S i In this column, 0 represents the object plane, 35 (IMG) represents the image plane, and surface numbers 1 to 34 are the surfaces of each lens, aperture stop, and protective glass from the object plane to the image plane. It should be noted that the cemented surfaces of different lenses in the cemented lens group are represented as the same surface.

[0129] The focusing data parameters of this embodiment are as follows:

[0130] NO. I II III D(0) 300 600 100 RED 0.03 0.01 0.07 f 8.05 8.00 8.21 D(1) 1.47 1.11 2.74 D(2) 1.77 2.13 0.50

[0131] like Fig.12 As shown, the field of view of this embodiment reaches 99.1°, the spherical aberration in the aberration diagrams is controlled within 0.01mm, the astigmatism and field curvature are controlled within 0.05mm, and the optical distortion is less than 0.6%, meeting all the parameter requirements of machine vision lenses. Figure 13-15 As shown, when the working distances are 300mm, 100mm and 600mm respectively, the full image height MTF in the figure is >0.25@150lp / mm, which meets the imaging requirements of high pixels, large target surface and wide working distance, and has high imaging quality.

[0132] Embodiment 4:

[0133] like Figure 16-20 As shown, a large-target-area and large-angle machine vision lens includes a first lens group G arranged in sequence from the object plane to the image plane 1 , aperture ST, second lens group G 2 , the third lens group G 3 Among them, the first lens group G 1 The optical elements L are arranged in sequence from the object plane to the image plane. 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 、Optical element L 15 、Optical element L 16 and optical element L 17 , the second lens group G 2 The optical elements L are arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , the third lens group G 3 The optical elements L are arranged in sequence from the object plane to the image plane. 31 、Optical element L 32 、Optical element L 33 and optical element L 34 .

[0134] Specifically, Fig.16 As shown, L11 is a positive meniscus lens, L 12 is a negative meniscus lens, L 13 is a negative meniscus lens, L 14 is a negative meniscus lens, L 15 is a double concave negative lens, L 16 It is a cemented lens group composed of a negative meniscus lens and a double convex lens arranged in sequence from the object plane to the image plane. 17 is a biconvex positive lens; L 21 is a double concave negative lens, L 22 It is a cemented lens group consisting of a double convex positive lens and a negative meniscus lens arranged in sequence from the object plane to the image plane; L 31 It is a cemented lens group consisting of a double convex positive lens and a double concave negative lens arranged in sequence from the object plane to the image plane. 32 is a biconvex positive lens, L 33 is a negative meniscus lens, L 34 The invention is a cemented lens group composed of a negative meniscus lens, a double convex positive lens and a negative meniscus lens which are arranged in sequence from the object plane to the image plane. Fig.16 The middle arrow indicates the second lens group G 2 The focusing group can be moved along the optical axis for focusing. 3 There is also an image plane protection glass CG in between.

[0135] The parameters of the lens of this embodiment satisfy: f = 8.00, Fno = 2.8, θ = 50.35°. The values ​​of each conditional expression are as follows:

[0136] Conditional Number (1) (2) (3) (4) (5) (6) (7) (8) Value -0.15 -0.06 -1.57 4.93 1.49 70.42 1.901 -7.61

[0137] The optical data parameters of each lens of the lens are as follows:

[0138]

[0139]

[0140] In the above table, the surface number S i In this column, 0 represents the object plane, 34 (IMG) represents the image plane, and surface numbers 1 to 33 are the surfaces of each lens, aperture stop, and protective glass from the object plane to the image plane. It should be noted that the cemented surfaces of different lenses in the cemented lens group are represented as the same surface.

[0141] The focusing data parameters of this embodiment are as follows:

[0142] NO. I II III D(0) 300 600 100 RED 0.02 0.01 0.07 f 8.00 7.94 8.21 D(1) 1.92 1.26 4.18 D(2) 2.77 3.42 0.50

[0143] like Fig.17As shown, the field of view of this embodiment reaches 100.7°, the spherical aberration in the aberration diagrams is controlled within 0.01mm, the astigmatism and field curvature are controlled within 0.05mm, and the optical distortion is less than 0.6%, meeting all the parameter requirements of machine vision lenses. Figure 18-20 As shown, when the working distances are 300mm, 100mm and 600mm respectively, the full image height MTF in the figure is >0.25@150lp / mm, which meets the imaging requirements of high pixels, large target surface and wide working distance, and has high imaging quality.

[0144] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] The above-described embodiments only express the more specific and detailed embodiments described in this application, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of this application, which all belong to the protection scope of this application. Therefore, the protection scope of the patent in this application shall be based on the attached claims.

Claims

1. A machine vision lens with a large target area and a large viewing angle, characterized in that: The large-target-area and large-angle machine vision lens comprises a first lens group G1, a second lens group G2 and a third lens group G3 with positive refractive power, which are arranged in sequence from the object plane to the image plane. When focusing, the first lens group G1 and the third lens group G3 are fixed relative to the image plane, and the second lens group G2 moves along the optical axis; The large-image-area and large-angle machine vision lens also meets the following conditions: Wherein, f1 is the focal length of the first lens group G1, f2 is the focal length of the second lens group G2, and f 12 is the combined focal length of the first lens group G1 and the second lens group G2, and f is the focal length of the optical system; The first lens group G1 includes optical elements L with positive refractive power arranged in sequence from the object plane to the image plane. 11 , an optical element L having negative optical power 12 , an optical element L having negative optical power 13 , an optical element L having negative optical power 14 and an optical element L having negative optical power 15 , and the following conditions are met: Among them, f a The optical element L 11 、Optical element L 12 、Optical element L 13 、Optical element L 14 and optical element L 15 The synthetic focal length of The optical element L 11 It is a meniscus lens with the convex surface facing the object plane and meets the following conditions: Wherein, TTL is the total optical length of the machine vision lens, and D is the optical element L 11 The maximum effective radius of the machine vision lens, θ is the half field of view angle; The second lens group G2 includes optical elements L arranged in sequence from the object plane to the image plane. 21 and optical element L 22 , the optical element L 21 is a single lens, the optical element L 22 It is a single lens or a cemented lens group; The third lens group G3 includes an optical element L 31 , the optical element L 31 It is a cemented lens group and meets the following conditions: Among them, f 31 The optical element L 31 , f3 is the focal length of the third lens group G3.

2. The large-target-area and large-angle machine vision lens according to claim 1, characterized in that: The first lens group G1 further includes optical elements L arranged in sequence from the object plane to the image plane. 16 and optical element L 17 , the optical element L 16 Located in the optical element L 15 The optical element L is on the image side and is a cemented lens group. 17 It is a single lens.

3. The large-target-area and large-angle machine vision lens according to claim 2, characterized in that: The first lens group G1 also includes an optical element L 17 Optical element L on the image side 18 , the optical element L 18 It is a single lens.

4. The large-target-area and large-angle machine vision lens according to claim 1, characterized in that: The optical element L 11 The following conditions are also met: n d1 ≤1.80 v d1 ≥43 Among them, n d1 The optical element L 11 The d-line refractive index, v d1 The optical element L 11 The Abbe number of .

5. The large-target-area and large-angle machine vision lens according to claim 1, characterized in that: The optical element L 12 、Optical element L 13 and optical element L 14 All are meniscus lenses with the convex surface facing the object plane and meet the following conditions: (n d2 +n d3 +n d4 ) / 3≥1.9 Among them, n d2 The optical element L 12 The d-line refractive index, n d3 The optical element L 13 The d-line refractive index, n d4 The optical element L 14 The d-line refractive index.

6. The large-target-area and large-angle machine vision lens according to claim 1, characterized in that: The large-target-area and large-angle machine vision lens further includes a stop ST, and the stop ST is located between the first lens group G1 and the second lens group G2.

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