High-precision image space telecentric lens with extremely low telecentricity

Abstract

The utility model relates to the technical field of optical lenses, in particular to a high-precision image space telecentric lens with extremely low telecentricity, which comprises a first lens, a second lens arranged on one side of the first lens, a third lens arranged on one side of the second lens, a fourth lens arranged on one side of the third lens and a fifth lens arranged on one side of the fourth lens. The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are arranged in a coaxial structure, the two sides of the first lens are a first object side face and a first image side face respectively, and the two sides of the second lens are a second object side face and a second image side face respectively. And two sides of the third lens are respectively a third object side surface and a third image side surface. The utility model solves the problems that the telecentricity of the lens is usually larger, and when the telecentricity is large, an obvious inclined hole can be punched when a thicker material is punched and cut, so that a certain error exists in precision processing.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to a high-precision image-side telecentric lens with extremely small telecentricity. Background Technology

[0002] Optical lenses are essential components in machine vision systems, directly affecting image quality and the implementation and effectiveness of algorithms. Optical lenses can be categorized by focal length (short focal length, medium focal length, telephoto), field of view (wide-angle, standard, telephoto), and structure (fixed aperture prime lens, manual aperture prime lens, automatic aperture prime lens, manual zoom lens, automatic zoom lens, automatic aperture motorized zoom lens, and motorized triple-variable (aperture, focal length, and focus all variable) lens, etc.

[0003] Chinese Patent Application No. CN202111351349.6 discloses an ultraviolet lens and its optical system, as well as a marking device, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the incident light direction; the first and second lenses are both negative meniscus lenses bent towards the incident light direction; the third and fourth lenses are both positive meniscus lenses bent towards the incident light direction; and the fifth and sixth lenses are both biconvex lenses. The ultraviolet laser scanning lens of this invention has a small spot convergence size, small telecentricity and relative distortion, and a large front-to-back working distance, which can be used in conjunction with a two-dimensional scanning galvanometer to achieve high-precision marking applications.

[0004] In existing technologies, the telecentricity of lenses is usually large. When drilling and cutting thicker materials, a large telecentricity will result in a noticeable oblique hole, leading to certain errors during precision machining. To address this, we propose a high-precision image-side telecentric lens with extremely small telecentricity. Utility Model Content

[0005] This utility model is proposed to address the shortcomings of existing technologies by providing a high-precision image-square telecentric lens with extremely small telecentricity. This high-precision image-square telecentric lens with extremely small telecentricity solves the problem that lenses with large telecentricity usually produce noticeable oblique holes when drilling and cutting thicker materials, leading to certain errors in precision machining.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-precision image-side telecentric lens with extremely small telecentricity includes a first lens, a second lens disposed on one side of the first lens, a third lens disposed on one side of the second lens, a fourth lens disposed on one side of the third lens, a fifth lens disposed on one side of the fourth lens, and a sixth lens disposed on one side of the fifth lens. The first, second, third, fourth, fifth, and sixth lenses are arranged in a coaxial structure. The two sides of the first lens are respectively a first object-side surface and a first image-side surface; the two sides of the second lens are respectively a second object-side surface and a second image-side surface; the two sides of the third lens are respectively a third object-side surface and a third image-side surface; the two sides of the fourth lens are respectively a fourth object-side surface and a fourth image-side surface; the two sides of the fifth lens are respectively a fifth object-side surface and a fifth image-side surface; and the two sides of the sixth lens are respectively a sixth object-side surface and a sixth image-side surface.

[0008] Preferably, the first object side is convex and the first image side is concave.

[0009] The second object side is convex, and the second image side is convex.

[0010] Both the side surface of the third object and the side surface of the third image are concave.

[0011] The fourth object side is concave, and the fourth image side is convex.

[0012] The fifth object side surface is concave, and the fifth image side surface is convex.

[0013] Both the side view of the sixth object and the side view of the sixth image are planar.

[0014] Preferably, the radius of curvature of the side of the first object in the vertical direction is 26.6±5% mm, and the radius of curvature of the side of the first image in the vertical direction is 299.6±5% mm.

[0015] The radius of curvature of the second object's side surface in the vertical direction is 20.7±5% mm, and the radius of curvature of the second image's side surface in the vertical direction is 39.2±5% mm.

[0016] The radius of curvature of the third object's side surface in the vertical direction is 39.3±5% mm, and the radius of curvature of the third image's side surface in the vertical direction is 20.2±5% mm.

[0017] The radius of curvature of the fourth object's side surface in the vertical direction is 194.9 ± 5% mm, and the radius of curvature of the fourth image's side surface in the vertical direction is 40.4 ± 5% mm.

[0018] The radius of curvature of the fifth object's side surface in the vertical direction is 242.9 ± 5% mm, and the radius of curvature of the fifth image's side surface in the vertical direction is 46.4 ± 5% mm.

[0019] Preferably, the refractive indices of the first lens, second lens, third lens, fourth lens, fifth lens and sixth lens are all between 1.37 and 2.0, and the Abbe constants are all between 30 and 85.

[0020] Preferably, the center-to-center distance between the first lens and the second lens is 27.5 ± 5% mm;

[0021] The center-to-center distance between the second lens and the third lens is 1.7 ± 5% mm;

[0022] The center-to-center distance between the third lens and the fourth lens is 38.6 ± 5% mm;

[0023] The center-to-center distance between the fourth lens and the fifth lens is 0.9 ± 5% mm;

[0024] The center-to-center distance between the fifth lens and the sixth lens is 0.5 ± 5% mm.

[0025] Preferably, the center thickness of the first lens is 3.5 ± 5% mm;

[0026] The center thickness of both the second lens and the fourth lens is 3.8 ± 5% mm;

[0027] The center thickness of the third lens is 3.3 ± 5% mm;

[0028] The center thickness of both the fifth lens and the sixth lens is 3±5% mm.

[0029] Preferably, the outer diameters of the first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens are all 26±5% mm.

[0030] In summary, this utility model provides a high-precision image-side telecentric lens with extremely small telecentricity, resulting in a very small diffusion range of the focused spot, concentrated energy at the focal point, and excellent correction of on-axis and off-axis aberrations.

[0031] The field curvature of the sagittal and meridional axes is controlled to be less than 0.01 mm, and the maximum distortion is almost 0%, which has reached the ideal state.

[0032] The angle at which the maximum field of view ray is incident on the image plane is 0.00001959°, which is much smaller than 0.0001°, reaching the ideal state. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of this utility model;

[0034] Figure 2 This is a schematic diagram of the dispersion pattern of this utility model;

[0035] Figure 3 This is a schematic diagram of the modulation transfer function (MTF) diagram of this utility model;

[0036] Figure 4 This is a schematic diagram of the astigmatism and distortion of this utility model;

[0037] Figure 5 This is a schematic diagram of the telecentricity of this utility model.

[0038] In the diagram: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens. Detailed Implementation

[0039] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0040] like Figure 1 As shown, a high-precision image-side telecentric lens with extremely small telecentricity includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6, which are coaxially arranged along the transmission direction of the incident light. The refractive indices of the first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, and sixth lens 6 are all between 1.37 and 2.0, and the Abbe constants are all between 30 and 85. The two sides of the first lens 1 are the first object-side and the first image-side, respectively; the two sides of the second lens 2 are the second object-side and the second image-side, respectively; the two sides of the third lens 3 are the third object-side and the third image-side, respectively; the two sides of the fourth lens 4 are the fourth object-side and the fourth image-side, respectively; the two sides of the fifth lens 5 are the fifth object-side and the fifth image-side, respectively; and the two sides of the sixth lens 6 are the sixth object-side and the sixth image-side.

[0041] The first object's side surface is convex, and the first image's side surface is concave; the second object's side surface is convex, and the second image's side surface is convex; both the third object's side surface and the third image's side surface are concave; the fourth object's side surface is concave, and the fourth image's side surface is convex; the fifth object's side surface is concave, and the fifth image's side surface is convex; both the sixth object's side surface and the sixth image's side surface are planar.

[0042] The vertical radius of curvature of the side surface of the first object is 26.6±5% mm, and the vertical radius of curvature of the side surface of the first image is 299.6±5% mm; the vertical radius of curvature of the side surface of the second object is 20.7±5% mm, and the vertical radius of curvature of the side surface of the second image is 39.2±5% mm; the vertical radius of curvature of the side surface of the third object is 39.3±5% mm, and the vertical radius of curvature of the side surface of the third image is 20.2±5% mm; the vertical radius of curvature of the side surface of the fourth object is 194.9±5% mm, and the vertical radius of curvature of the side surface of the fourth image is 40.4±5% mm; the vertical radius of curvature of the side surface of the fifth object is 242.9±5% mm, and the vertical radius of curvature of the side surface of the fifth image is 46.4±5% mm.

[0043] The center-to-center distance between the first lens 1 and the second lens 2 is 27.5 ± 5% mm;

[0044] The center-to-center distance between the second lens 2 and the third lens 3 is 1.7 ± 5% mm;

[0045] The center-to-center distance between the third lens 3 and the fourth lens 4 is 38.6 ± 5% mm;

[0046] The center-to-center distance between the fourth lens 4 and the fifth lens 5 is 0.9 ± 5% mm;

[0047] The center spacing between the fifth lens 5 and the sixth lens 6 is 0.5 ± 5% mm.

[0048] The center thickness of the first lens 1 is 3.5 ± 5% mm;

[0049] The center thickness of both the second lens 2 and the fourth lens 4 is 3.8 ± 5% mm;

[0050] The center thickness of the third lens 3 is 3.3 ± 5% mm;

[0051] The center thickness of both the fifth lens 5 and the sixth lens 6 is 3±5% mm.

[0052] The outer diameters of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are all 26±5% mm.

[0053] like Figure 2 As shown, the blur pattern of the high-precision image-square telecentric lens with extremely small telecentricity has a geometric blur circle within 0.002mm across the entire field of view, achieving an ideal state. The focusing spot blur range of this high-precision image-square telecentric lens with extremely small telecentricity is very small, the energy at the focal point is concentrated, and the on-axis and off-axis aberrations are well corrected.

[0054] like Figure 3As shown, the modulation transfer function (MTF) plot of a high-precision image-square telecentric lens with extremely small telecentricity is shown, where the horizontal axis represents the resolution in line pairs / mm. All fields of view are concentrated at the diffraction limit, and the MTF is still around 0.6 when the resolution reaches 20 line pairs, which meets the requirements of laser processing.

[0055] like Figure 4 As shown, the astigmatism and distortion diagrams of a high-precision image-square telecentric lens with extremely low telecentricity are shown. The left diagram is the astigmatism diagram, where the vertical axis +Y represents the size of the field of view and the horizontal axis is in μm. In the right diagram, +Y represents the size of the field of view, and the horizontal axis is in percentage. The field curvature of the sagittal and meridional axes is controlled to <0.01mm, and the maximum distortion is almost equal to 0%, which has reached the ideal state.

[0056] like Figure 5 As shown, the telecentricity of a high-precision image-side telecentric lens with extremely small telecentricity is given. The RAID function represents the actual incident angle of the light ray, i.e., the angle between the incident ray and the normal to the surface, expressed in degrees. In the figure, the maximum field of view is set to 1, and the RAID function is used to represent the angles of the light rays incident on the image plane for fields of view of 0, 0.1, 0.3, 0.5, 0.7, and 1. The angle of the maximum field of view light rays incident on the image plane shown in the figure is 0.00001959°, which is much smaller than 0.0001 degrees, reaching the ideal state.

[0057] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A high-precision image-square telecentric lens with extremely small telecentricity, characterized in that, The system includes a first lens (1), a second lens (2) disposed on one side of the first lens (1), a third lens (3) disposed on one side of the second lens (2), a fourth lens (4) disposed on one side of the third lens (3), a fifth lens (5) disposed on one side of the fourth lens (4), and a sixth lens (6) disposed on one side of the fifth lens (5). The first lens (1), second lens (2), third lens (3), fourth lens (4), fifth lens (5), and sixth lens (6) are arranged in a coaxial structure. The first lens (1) has a first lens (2) disposed on one side of the second lens (2), a second lens (3), a third lens (4), a fifth lens (5), and a sixth lens (6) disposed on one side of the third lens (3). The object side and the first image side are respectively the second object side and the second image side on both sides of the second lens (2), the third object side and the third image side on both sides of the third lens (3), the fourth object side and the fourth image side on both sides of the fourth lens (4), the fifth object side and the fifth image side on both sides of the fifth lens (5), and the sixth object side and the sixth image side on both sides of the sixth lens (6). The vertical radius of curvature of the first object side is 26.6±5%mm, and the vertical radius of curvature of the first image side is 299.6±5%mm. The radius of curvature of the second object's side surface in the vertical direction is 20.7±5%mm, and the radius of curvature of the second image's side surface in the vertical direction is 39.2±5%mm; The radius of curvature of the third object's side surface in the vertical direction is 39.3±5%mm, and the radius of curvature of the third image's side surface in the vertical direction is 20.2±5%mm; The radius of curvature of the fourth object's side surface in the vertical direction is 194.9±5%mm, and the radius of curvature of the fourth image's side surface in the vertical direction is 40.4±5%mm. The radius of curvature of the fifth object side in the vertical direction is 242.9±5%mm, the radius of curvature of the fifth image side in the vertical direction is 46.4±5%mm, the refractive indices of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all between 1.37 and 2.0, the Abbe constants are all between 30 and 85, and the center interval between the first lens (1) and the second lens (2) is 27.5±5%mm; The center distance between the second lens (2) and the third lens (3) is 1.7 ± 5% mm; The center distance between the third lens (3) and the fourth lens (4) is 38.6 ± 5% mm; The center interval between the fourth lens (4) and the fifth lens (5) is 0.9 ± 5% mm; The center interval between the fifth lens (5) and the sixth lens (6) is 0.5±5%mm, and the center thickness of the first lens (1) is 3.5±5%mm; The center thickness of both the second lens (2) and the fourth lens (4) is 3.8 ± 5% mm; The center thickness of the third lens (3) is 3.3 ± 5% mm; The center thickness of the fifth lens (5) and the sixth lens (6) is 3±5% mm, and the outer diameter of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) is 26±5% mm.

2. The high-precision image-side telecentric lens with extremely small telecentricity according to claim 1, characterized in that, The first object's side surface is convex, and the first image's side surface is concave. The second object side is convex, and the second image side is convex. Both the side surface of the third object and the side surface of the third image are concave. The fourth object side is concave, and the fourth image side is convex. The fifth object side surface is concave, and the fifth image side surface is convex. Both the side surface of the sixth object and the side surface of the sixth image are planar.

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