Near-infrared floating focusing machine vision lens

Abstract

The utility model relates to a near-infrared floating focusing machine vision lens, and belongs to the technical field of imaging optical system design. Comprising a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a diaphragm STOP, a sixth lens G6, a seventh lens G7, an eighth lens G8, a ninth lens G9, a tenth lens G10, an eleventh lens G11 and a protection lens which are sequentially arranged from an object space to an image space along an optical axis. According to the utility model, eleven full-spherical lenses are used, floating focusing is adopted, and the diaphragm front lens group is controlled to move so as to cooperate with work under different working distances. The lens can be suitable for a chip with the size of 1 '', has a large aperture, and meets the requirements of high illumination, low chromatic aberration, small distortion and the like of a semiconductor detection lens in the field of machine vision detection.

Description

Technical Field

[0001] The utility model belongs to the technical field of imaging optical system design, and particularly relates to a machine vision lens with near-infrared floating focusing. Background Technique

[0002] At present, the intelligent detection of photovoltaic cells based on machine vision has developed rapidly. By detecting the infrared light excited by the cells, the defects of the cells can be monitored in real time. For such scenarios, the lens needs a large aperture to ensure sufficient light input and focus on different object distances. However, the quality of related lenses on the market varies, and the working distance and application wavelength range cannot well meet the usage requirements. Content of the Utility Model

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a machine vision lens with near-infrared floating focusing, so as to achieve the characteristics of large aperture, large target surface, small distortion, long working distance, etc., be sensitive to the fluorescence band emitted by cell detection, and have good chromatic aberration and spherical aberration correction.

[0004] To achieve the above purpose, the technical solution of the utility model is: a machine vision lens with near-infrared floating focusing, including a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a diaphragm STOP, a sixth lens G6, a seventh lens G7, an eighth lens G8, a ninth lens G9, a tenth lens G10, and an eleventh lens G11, which are sequentially arranged along the optical axis from the object side to the image side.

[0005] In an embodiment of the utility model, the first lens G1 is a convex plano-positive lens, the second lens G2 is a meniscus negative lens, the third lens G3 is a meniscus negative lens, the fourth lens G4 is a biconcave negative lens, the fifth lens G5 is a biconvex positive lens, the sixth lens G6 is a meniscus positive lens, the seventh lens G7 is a biconvex positive lens, the eighth lens G8 is a biconcave negative lens, the ninth lens G9 is a biconvex positive lens, the tenth lens G10 is a meniscus positive lens, and the eleventh lens G11 is a convex plano-negative lens.

[0006] In an embodiment of the utility model, the seventh lens G7 and the eighth lens G8 are glued together to form a first glued lens.

[0007] In an embodiment of the utility model, the tenth lens G10 and the eleventh lens G11 are glued together to form a second glued lens.

[0008] In an embodiment of the present utility model, the air gap between the first lens G1 and the second lens G2 is 0.15 mm, the air gap between the second lens G2 and the third lens G3 is 2.51 mm, the air gap between the third lens G3 and the fourth lens G4 is adjustable, the air gap between the fourth lens G4 and the fifth lens G5 is 5.17 mm, the air gap between the fifth lens G5 and the diaphragm STOP is adjustable, the air gap between the diaphragm STOP and the sixth lens G6 is 7.93 mm, the air gap between the sixth lens G6 and the seventh lens G7 is 0.15 mm, the air gap between the eighth lens G8 and the ninth lens G9 is 7.13 mm, and the air gap between the ninth lens G9 and the tenth lens G10 is 0.15 mm.

[0009] In an embodiment of the present utility model, the first lens G1, the second lens G2, and the third lens G3 form a first lens group L1, the fourth lens G4 and the fifth lens G5 form a second lens group L2, and the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10, and the eleventh lens G11 form a third lens group L3.

[0010] In an embodiment of the present utility model, the refractive indices and dispersion coefficients from the first lens G1 to the eleventh lens G11 satisfy:

[0011] 1.60 ≤ n1 ≤ 1.80; 50.0 ≤ v1 ≤ 65.0;

[0012] 1.70 ≤ n2 ≤ 1.90; 20.0 ≤ v2 ≤ 35.0;

[0013] 1.75 ≤ n3 ≤ 1.95; 20.0 ≤ v3 ≤ 35.0;

[0014] 1.50 ≤ n4 ≤ 1.70; 35.0 ≤ v4 ≤ 50.0;

[0015] 1.70 ≤ n5 ≤ 1.90; 30.0 ≤ v5 ≤ 50.0;

[0016] 1.60 ≤ n6 ≤ 1.80; 45.0 ≤ v6 ≤ 60.0;

[0017] 1.50 ≤ n7 ≤ 1.70; 60.0 ≤ v7 ≤ 75.0;

[0018] 1.60 ≤ n8 ≤ 1.80; 25.0 ≤ v8 ≤ 40.0;

[0019] 1.60 ≤ n9 ≤ 1.80; 45.0 ≤ v9 ≤ 60.0;

[0020] 1.80 ≤ n10 ≤ 2.00; 20.0 ≤ v10 ≤ 35.0;

[0021] 1.75 ≤ n11 ≤ 1.95; 30.0 ≤ v11 ≤ 45.0;

[0022] Wherein, nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, nd9, nd10, and nd11 are the refractive indices of the first lens G1 to the eleventh lens G11 respectively; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, vd9, vd10, and vd11 are the dispersion coefficients of the first lens G1 to the eleventh lens G11 respectively.

[0023] In an embodiment of the present utility model, the first lens group L1, the second lens group L2, and the third lens group L3 are all spherical glass lenses.

[0024] In an embodiment of the present utility model, an image sensor chip is provided on the image side, and a filter group and / or a protective glass are provided between the eleventh lens G11 and the image sensor chip.

[0025] In an embodiment of the present utility model, the designed spectral line of the near-infrared floating focus machine vision lens is near-infrared light with a wavelength of 900 nm - 1500 nm. The maximum F-number is 1.6 at full aperture. A large aperture is used to achieve a large light input. The image plane size is Φ = 16 mm, and the applicable image sensor chip size is 1".

[0026] Compared with the prior art, the present utility model has at least the following beneficial effects:

[0027] 1. Two groups of cemented lens groups are used to correct chromatic aberration. A floating focus structure is adopted to achieve clear imaging within the object distance range from 300 mm to infinity. The positive and negative optical powers are matched, and the structure is reasonable.

[0028] 2. The designed spectral line is 900 - 1500 nm near-infrared light. The maximum F-number is 1.6 at full aperture. A large aperture is used to achieve a large light input. The image plane size is Φ = 16 mm, and the applicable chip size is 1", achieving a large target surface and performing better under low light conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a near-infrared floating focus machine vision lens of the present utility model;

[0030] Figure 2 It is an MTF graph of Embodiment 1 of the present utility model when the object distance is 600 mm;

[0031] Figure 3 It is a lateral chromatic aberration image of Embodiment 1 of the present utility model when the object distance is 600 mm;

[0032] Figure 4 This is the optical distortion curve graph of Embodiment 1 of the present utility model when the object distance is 600 mm.

[0033] In the figure, G1 is the first lens; G2 is the second lens; G3 is the third lens; G4 is the fourth lens; G5 is the fifth lens; G6 is the sixth lens; G7 is the seventh lens; G8 is the eighth lens; G9 is the ninth lens; G10 is the tenth lens; G11 is the eleventh lens; H1 is the filter group / protective glass; STOP is the variable aperture; IMA is the imaging surface. Detailed implementation manners

[0034] The technical solution of the present utility model will be specifically described below in conjunction with the accompanying drawings.

[0035] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation to the present utility model.

[0036] Refer to Figure 1 As shown, a machine vision lens with near-infrared floating focus for an embodiment of the present utility model, the optical system of the lens includes a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, an aperture STOP, a sixth lens G6, a seventh lens G7, an eighth lens G8, a ninth lens G9, a tenth lens G10, an eleventh lens G11 and a protective lens, which are sequentially arranged at intervals along the incident light path from front to back.

[0037] In the embodiment of the present utility model, the first lens G1 is a convex plano-positive lens, the second lens G2 is a meniscus negative lens, the third lens G3 is a meniscus negative lens, the fourth lens G4 is a biconcave negative lens, the fifth lens G5 is a biconvex positive lens, the sixth lens G6 is a meniscus positive lens, the seventh lens G7 is a biconvex positive lens, the eighth lens G8 is a biconcave negative lens, the ninth lens G9 is a biconvex positive lens, the tenth lens G10 is a meniscus positive lens, and the eleventh lens G11 is a convex plano-negative lens.

[0038] In the embodiment of the present utility model, the seventh lens G7 and the eighth lens G8 are glued together to form a first glued lens, and the tenth lens G10 and the eleventh lens G11 are glued together to form a second glued lens.

[0039] In the embodiment of the present utility model, the air gap between the first lens G1 and the second lens G2 is 0.15 mm, the air gap between the second lens G2 and the third lens G3 is 2.51 mm, the air gap between the third lens G3 and the fourth lens G4 is adjustable, the air gap between the fourth lens G4 and the fifth lens G5 is 5.17 mm, the air gap between the fifth lens G5 and the aperture STOP is adjustable, the air gap between the aperture STOP and the sixth lens G6 is 7.93 mm, the air gap between the sixth lens G6 and the seventh lens G7 is 0.15 mm, the air gap between the eighth lens G8 and the ninth lens G9 is 7.13 mm, and the air gap between the ninth lens G9 and the tenth lens G10 is 0.15 mm.

[0040] In the embodiment of the present utility model, the first lens G1, the second lens G2 and the third lens G3 form the first lens group L1, the fourth lens G4 and the fifth lens G5 form the second lens group L2, and the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10 and the eleventh lens G11 form the third lens group L3.

[0041] In the embodiment of the present utility model, the refractive indices and dispersion coefficients of the lenses from the first lens to the eleventh lens satisfy:

[0042] 1.60 ≤ n1 ≤ 1.80; 50.0 ≤ v1 ≤ 65.0;

[0043] 1.70 ≤ n2 ≤ 1.90; 20.0 ≤ v2 ≤ 35.0;

[0044] 1.75 ≤ n3 ≤ 1.95; 20.0 ≤ v3 ≤ 35.0;

[0045] 1.50 ≤ n4 ≤ 1.70; 35.0 ≤ v4 ≤ 50.0;

[0046] 1.70 ≤ n5 ≤ 1.90; 30.0 ≤ v5 ≤ 50.0;

[0047] 1.60 ≤ n6 ≤ 1.80; 45.0 ≤ v6 ≤ 60.0;

[0048] 1.50 ≤ n7 ≤ 1.70; 60.0 ≤ v7 ≤ 75.0;

[0049] 1.60 ≤ n8 ≤ 1.80; 25.0 ≤ v8 ≤ 40.0;

[0050] 1.60 ≤ n9 ≤ 1.80; 45.0 ≤ v9 ≤ 60.0;

[0051] 1.80 ≤ n10 ≤ 2.00; 20.0 ≤ v10 ≤ 35.0;

[0052] 1.75 ≤ n11 ≤ 1.95; 30.0 ≤ v11 ≤ 45.0;

[0053] Wherein, nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, nd9, nd10, and nd11 are the refractive indices of the first lens to the eleventh lens respectively; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, vd9, vd10, and vd11 are the Abbe numbers of the first lens to the eleventh lens respectively.

[0054] In the embodiment of the present utility model, the first lens group L1, the second lens group L2, and the third lens group L3 are all spherical glass lenses.

[0055] In the embodiment of the present utility model, an image sensor chip is disposed on the image side, and a filter group and / or a protective glass are disposed between the eleventh lens and the image sensor chip.

[0056] Taking a specific embodiment for illustration, the curvature radii, thicknesses of all surfaces, and the refractive indices and Abbe numbers of the materials of the glass used in this optical system are as follows:

[0057] Table 1 Detailed optical data of a near-infrared floating focus machine vision lens:

[0058]

[0059] In this specific embodiment, the focusing movement distances at different working distances need to meet the parameter requirements shown in Table 2.

[0060] Table 2 is the parameter table of the focusing movement distances at different working distances

[0061] Working distance (mm) 300 600 1000 Infinity Focus adjustment amount 1: Distance between lens group L1 and lens group L2 (mm) 9.25 10.59 11.14 12.00 Focus adjustment amount 2: Distance between lens group L2 and diaphragm (mm) 1.92 1.00 0.64 0.100 Focus adjustment amount 3: Distance between lens group L3 and image plane (mm) 11.37 9.70 8.97 7.80

[0062] In this specific embodiment, this lens achieves the following optical specifications:

[0063] (1) The working object distance range of the lens is from 300 mm to infinity;

[0064] (2) The maximum image plane of the lens is φ16 mm, and it can be adapted to a chip with a 1-inch target surface;

[0065] (3) The focal length of the lens is 35 mm;

[0066] (4) The MTF of the lens is greater than 0.2 at 120 lp / mm line pairs, and it can provide a clear image;

[0067] (5) The F number of the lens is 1.6, and the relative illumination is greater than 80% within the working distance range;

[0068] The distortion at all object distances is less than 1%;

[0069] (7)The CRA is less than 3°.

[0070] See Figure 1 , combining Table 1 and Table 2, it can be seen that: in this specific embodiment, the imaging quality at different object distances is ensured by the front and back movement of the first lens group and the second lens group.

[0071] In the specific embodiment, the focal length f of the optical imaging lens is 35 mm; the maximum aperture value FNO is 1.6; the image plane size Φ is 16 mm; the distance TTL from the object side of the first lens to the imaging plane on the optical axis is 143.94 mm. The front and back groups are used for floating focusing. By controlling the movement of the first lens group and the second lens group to cooperate with the lens working at different working distances, the distortion at the full object distance is less than 1%. It can be adapted to a 1-inch photosensitive chip (the effective target surface is Φ = 16 mm), and the imaging quality in the near-infrared band is good, and the chromatic aberration and spherical aberration are well corrected.

[0072] Figure 2 The MTF curve diagram of this specific embodiment at an object distance of 600 mm is shown. The abscissa is the spatial frequency of the MTF curve, with the unit of lp / mm, and the ordinate is the value of the modulation transfer function, representing the reduction degree of the image to the object. This diagram shows that the MTF of this lens is > 0.2 at 120 lp / mm.

[0073] Figure 3 The optical distortion curve diagram of this specific embodiment at an object distance of 600 mm is shown. The abscissa is the distortion percentage, and the ordinate is the normalized field height. This diagram shows that the distortion of this lens is < 1%.

[0074] This solution realizes an optical system of an optical lens with a large aperture, a large target surface, low chromatic aberration, and low distortion with a focal length of 35 mm through the above structure. The maximum F number on the image side is 1.6, the highest resolution can reach 120 lp / mm, and the maximum optical distortion of the full field of view is less than 1%; the floating focusing method is adopted to achieve a wide working distance and can be matched with the detection equipment of multiple manufacturers.

[0075] The above are the preferred embodiments of the present invention. All changes made according to the technical solutions of the present invention and whose functional effects do not exceed the scope of the technical solutions of the present invention shall fall within the protection scope of the present invention.

Claims

1. A near-infrared floating focus machine vision lens, characterized in that: The invention comprises a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, an aperture STOP, a sixth lens G6, a seventh lens G7, an eighth lens G8, a ninth lens G9, a tenth lens G10 and an eleventh lens G11 which are sequentially arranged along the optical axis from the object side to the image side; the first lens G1 is a convex-planar positive lens, the second lens G2 is a meniscus negative lens, the third lens G3 is a meniscus negative lens, the fourth lens G4 is a double-concave negative lens, the fifth lens G5 is a double-convex positive lens, the sixth lens G6 is a meniscus positive lens, the seventh lens G7 is a double-convex positive lens, the eighth lens G8 is a double-concave negative lens, the ninth lens G9 is a double-convex positive lens, the tenth lens G10 is a meniscus positive lens, and the eleventh lens G11 is a convex-planar negative lens; the seventh lens G7 and the eighth lens G8 are cemented to form a first cemented lens; the tenth lens G10 and the eleventh lens G11 are cemented to form a second cemented lens.

2. The near-infrared floating focus machine vision lens according to claim 1, characterized in that: The air interval between the first lens G1 and the second lens G2 is 0.15 mm, the air interval between the second lens G2 and the third lens G3 is 2.51 mm, the air interval between the third lens G3 and the fourth lens G4 is adjustable, the air interval between the fourth lens G4 and the fifth lens G5 is 5.17 mm, the air interval between the fifth lens G5 and the aperture STOP is adjustable, the air interval between the aperture STOP and the sixth lens G6 is 7.93 mm, the air interval between the sixth lens G6 and the seventh lens G7 is 0.15 mm, the air interval between the eighth lens G8 and the ninth lens G9 is 7.13 mm, and the air interval between the ninth lens G9 and the tenth lens G10 is 0.15 mm.

3. The near-infrared floating focus machine vision lens according to claim 1, characterized in that: The first lens G1, the second lens G2 and the third lens G3 form a first lens group L1, the fourth lens G4 and the fifth lens G5 form a second lens group L2, and the sixth lens G6, the seventh lens G7, the eighth lens G8, the ninth lens G9, the tenth lens G10 and the eleventh lens G11 form a third lens group L3.

4. The near-infrared floating focus machine vision lens according to claim 1, characterized in that: The refractive index and the Abbe coefficient of the first lens G1 to the eleventh lens G11 satisfy: 1.60≤n1≤1.80;50.0≤v1≤65.0; 1.70≤n2≤1.90;20.0≤v2≤35.0; 1.75≤n3≤1.95;20.0≤v3≤35.0; 1.50≤n4≤1.70;35.0≤v4≤50.0; 1.70≤n5≤1.90;30.0≤v5≤50.0; 1.60≤n6≤1.80;45.0≤v6≤60.0; 1.50≤n7≤1.70;60.0≤v7≤75.0; 1.60≤n8≤1.80;25.0≤v8≤40.0; 1.60≤n9≤1.80;45.0≤v9≤60.0; 1.80≤n10≤2.00;20.0≤v10≤35.0; 1.75≤n11≤1.95;30.0≤v11≤45.0; Among them, nd1, nd2, nd3, nd4, nd5, nd6, nd7, nd8, nd9, nd10 and nd11 are the refractive indices of the first lens G1 to the eleventh lens G11 respectively; vd1, vd2, vd3, vd4, vd5, vd6, vd7, vd8, vd9, vd10 and vd11 are the chromatic aberration coefficients of the first lens G1 to the eleventh lens G11 respectively.

5. The near-infrared floating focus machine vision lens according to claim 3, characterized in that: The first lens group L1, the second lens group L2 and the third lens group L3 are all spherical glass lenses.

6. The near-infrared floating focus machine vision lens according to claim 1, characterized in that: A photosensitive chip is arranged on the image side, and a filter group and / or protective glass is arranged between the eleventh lens G11 and the photosensitive chip.

7. The near-infrared floating focus machine vision lens according to claim 6, characterized in that: The design spectrum of the near-infrared floating focus machine vision lens is a near-infrared light wavelength of 900nm-1500nm. The maximum F number is 1.6 at full aperture, and a large aperture is used to achieve a large amount of light input. The image plane size is Φ=16mm, and the applicable photosensitive chip size is 1".

Images