Coaxial light large target surface telecentric lens with Kohler illumination
By designing a coaxial large target-surface telecentric lens with Cole lighting, the problem of low welding quality caused by low magnification of existing telecentric lenses is solved, and high resolution and large aperture imaging is achieved, which is suitable for high-end application scenarios.
Patent Information
- Application Number
- CN202421738822.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-22
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-07-22
AI Technical Summary
Due to the low magnification, existing telecentric lenses cannot effectively monitor the welding process of electronic components, resulting in low welding quality, especially in high-end application scenarios.
A coaxial large target surface telecentric lens with Korer illumination was designed, and a multi-lens combination structure and Korer illumination system were used to achieve high resolution and large aperture imaging.
Through large-scale target imaging and high-resolution design, the monitoring efficiency of the welding process is improved, the occurrence of quality problems is reduced, and it is suitable for high-end application scenarios.
Smart Images
Figure CN222800936U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of optical lenses, and in particular to a telecentric lens with a coaxial optical target surface and Kohler illumination. Background Art
[0002] The welding of electronic components is a key step in electronic manufacturing, which involves the selection and use of a variety of welding techniques and tools. The quality of welding directly affects the performance and reliability of electronic products.
[0003] With the rapid development of machine vision technology, more and more application scenarios require the use of telecentric lenses with high resolution and large aperture to complete positioning, detection, measurement and other tasks. Low-magnification lenses can play a monitoring role when the welding or placement requirements for larger electronic components are not strict, but there will be great deficiencies or misjudgments when monitoring smaller components, which will cause defects such as omissions, poor welding, component errors, etc. This is unacceptable for an enterprise, especially in high-end application scenarios that require high-precision and high-quality imaging. There is an urgent need for a telecentric lens that combines a coaxial light built-in lighting system with a large target surface, high resolution and large aperture to meet increasingly complex usage needs.
[0004] Therefore, a new telecentric lens is urgently needed. Utility Model Content
[0005] The utility model provides a telecentric lens with a coaxial optical target surface and Kohler illumination, which solves the problem that the existing telecentric lens cannot play a good monitoring role on the welding of electronic components due to low magnification.
[0006] The technical solution of the utility model is as follows: a coaxial optical enlargement target surface telecentric lens with Kohler illumination, the coaxial optical enlargement target surface telecentric lens comprising a housing, a front optical group and a rear optical group arranged in the housing, an aperture arranged between the front optical group and the rear optical group, and a Kohler illumination assembly arranged in the housing, the front optical group comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the optical axis direction, the rear optical group comprising a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens arranged in sequence along the optical axis direction; the Kohler illumination assembly is arranged on the side of the eighth lens, and the light of the Kohler illumination assembly is perpendicular to the optical axis;
[0007] Wherein, the second lens and the third lens are combined into a first cemented lens, the fifth lens and the sixth lens are combined into a second cemented lens, the aperture is located between the sixth lens and the seventh lens, and the tenth lens and the eleventh lens are combined into a third cemented lens;
[0008] The first lens, the third lens, the fourth lens and the fifth lens are all biconvex lenses, the second lens and the sixth lens are all biconcave lenses, the seventh lens, the eleventh lens and the twelfth lens are all negative meniscus lenses, the eighth lens is a cylindrical lens or a right-angle prism; the ninth lens is a biconcave lens, and the tenth lens is a positive meniscus lens.
[0009] As a further technical solution, the front surface curvature of the first lens is 52.088mm, the back surface curvature radius is -85.662mm, and the center thickness of the lens is 3.9mm; the front surface curvature radius of the second lens is -22.95mm, the back surface curvature radius is 29.23mm, and the center thickness of the lens is 1.3mm; the front surface curvature radius of the third lens is -22.95mm, the back surface curvature radius is -29.95mm, and the center thickness of the lens is 3.86mm; the front surface curvature radius of the fourth lens is 36.03mm, the back surface curvature radius is -34.26mm, and the center thickness of the lens is 5.13mm; the front surface curvature radius of the fifth lens is 31.49mm, the back surface curvature radius is -26.97mm, and the center thickness of the lens is 3.6mm; the front surface curvature radius of the sixth lens is -26.97mm, the back surface curvature radius is 30.15mm, and the center thickness of the lens is 1.25mm.
[0010] As a further technical solution, the distance between the second lens and the first lens is 40.7 mm; the distance between the fourth lens and the third lens is 0.30 mm; and the distance between the fifth lens and the fourth lens is 0.3 mm.
[0011] As a further technical solution, the distance between the aperture and the sixth lens is 14.3 mm, and the distance between the aperture and the seventh lens is 2.31 mm.
[0012] As a further technical solution, the front surface curvature of the seventh lens is 117.15mm, the rear surface curvature radius is -45.16mm, and the center thickness of the lens is 1.85mm; the front surface curvature radius of the eighth lens is infinity, the rear surface curvature radius is infinity, and the center thickness of the lens is 20mm; the front surface curvature of the ninth lens is -28.53mm, the rear surface curvature radius is 32.69mm, and the center thickness of the lens is 10mm; the front surface curvature radius of the tenth lens is -22.54mm, the rear surface curvature radius is 238.65mm, and the center thickness of the lens is 10mm; the front surface curvature radius of the eleventh lens is 238.65mm, the rear surface curvature radius is -33.53mm, and the center thickness of the lens is 7.78mm; the front surface curvature radius of the twelfth lens is -266.15mm, the rear surface curvature radius is -129.4mm, and the center thickness of the lens is 9.85mm.
[0013] As a further technical solution, the distance between the eighth lens and the seventh lens is 11.1 mm; the distance between the ninth lens and the eighth lens is 10.3 mm; the distance between the tenth lens and the ninth lens is 16.3 mm; the distance between the eleventh lens and the twelfth lens is 206.15 mm; and the distance from the twelfth lens to the image plane is 14.13 mm.
[0014] As a further technical solution, the material of the first lens is H-FK61B, and the effective aperture is Φ27.8mm; the material of the second lens is H-ZLAF55D, and the effective aperture is Φ17.5mm; the material of the third lens is H-FK61B, and the effective aperture is Φ18.5mm; the material of the fourth lens is H-LAF50B, and the effective aperture is Φ20mm; the material of the fifth lens is H-FK61B, and the effective aperture is Φ18mm; the material of the sixth lens is H-ZLAF55D, and the effective aperture is Φ17.5mm.
[0015] As a further technical solution, the seventh lens is made of H-ZF5, with an effective aperture of Φ14.6mm; the eighth lens is made of H-K9L, with an effective aperture of Φ20mm; the ninth lens is made of H-FK61B, with an effective aperture of Φ17mm; the tenth lens is made of H-F1, with an effective aperture of Φ24.4mm; the eleventh lens is made of H-LAK51A, with an effective aperture of Φ36.5mm; the twelfth lens is made of H-FK61B, with an effective aperture of Φ125mm.
[0016] The beneficial effects of the utility model are:
[0017] 1. Using large target surface imaging, the imaging inspection of large objects can be completed at one time to improve inspection efficiency and save costs;
[0018] 2. It can improve the magnification, especially for the inspection of small objects, to see more subtle problems, especially in AOI inspection to avoid major quality problems, expand the scope of application and use efficiency;
[0019] 3. It not only has the advantage of large target imaging, but also can meet the requirements of high resolution for details. The design concept of telecentric lens and diffraction limit makes the brightness and resolution of the whole picture uniform, and reduces the alignment error and reading error, thus improving the accuracy.
[0020] 4. The coaxial system with Kohler illumination can reduce the dependence on external light and the requirements for complex environments, improve the brightness of the object surface and make the brightness of the imaging surface more uniform, avoiding the phenomenon of inconsistent brightness of the picture. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0022] Figure 1 A schematic diagram of the structure of the matching parts of each lens provided by the utility model;
[0023] Figure 2 It is a schematic diagram of the structure where light shines on each lens;
[0024] Figure 3 Schematic diagram of the image plane resolution curve designed under diffraction limit conditions;
[0025] Figure 4 The spot diagram shows different viewing fields at different wavelengths;
[0026] Figure 5 Light trace diagram showing illumination uniformity of Kohler illumination.
[0027] In the figure: 1, the first lens; 2, the second lens; 3, the third lens; 4, the fourth lens; 5, the fifth lens; 6, the sixth lens; 7, the seventh lens; 8, the eighth lens; 9, the ninth lens; 10, the tenth lens; 11, the eleventh lens; 12, the twelfth lens; 13, the Kohler lens; 14, the focusing lens. DETAILED DESCRIPTION
[0028] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0029] like Figure 1-2 As shown, the utility model provides a coaxial optical enlargement target surface telecentric lens with Kohler illumination, the coaxial optical enlargement target surface telecentric lens comprises a housing, a front optical group and a rear optical group arranged in the housing, an aperture arranged between the front optical group and the rear optical group, and a Kohler illumination assembly arranged in the housing, the front optical group comprises 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 arranged in sequence along the optical axis direction, the rear optical group comprises a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11 and a twelfth lens 12 arranged in sequence along the optical axis direction; the Kohler illumination assembly is arranged on the side of the eighth lens 8, and the light of the Kohler illumination assembly is perpendicular to the optical axis;
[0030] The second lens 2 and the third lens 3 are combined into a first cemented lens, the fifth lens 5 and the sixth lens 6 are combined into a second cemented lens, the aperture is located between the sixth lens 6 and the seventh lens 7, and the tenth lens 10 and the eleventh lens 11 are combined into a third cemented lens;
[0031] The first lens 1, the third lens 3, the fourth lens 4 and the fifth lens 5 are all biconvex lenses, the second lens 2 and the sixth lens 6 are all biconcave lenses, the seventh lens 7, the eleventh lens 11 and the twelfth lens 12 are all negative meniscus lenses, the eighth lens 8 is a cylindrical lens or a right-angle prism; the ninth lens 9 is a biconcave lens, and the tenth lens 10 is a positive meniscus lens.
[0032] The front surface curvature of the first lens 1 is 52.088mm, the back surface curvature radius is -85.662mm, and the center thickness of the lens is 3.9mm; the front surface curvature radius of the second lens 2 is -22.95mm, the back surface curvature radius is 29.23mm, and the center thickness of the lens is 1.3mm; the front surface curvature radius of the third lens 3 is -22.95mm, the back surface curvature radius is -29.95mm, and the center thickness of the lens is 3.86mm; the front surface curvature radius of the fourth lens 4 is 36.03mm, the back surface curvature radius is -34.26mm, and the center thickness of the lens is 5.13mm; the front surface curvature radius of the fifth lens 5 is 31.49mm, the back surface curvature radius is -26.97mm, and the center thickness of the lens is 3.6mm; the front surface curvature radius of the sixth lens 6 is -26.97mm, the back surface curvature radius is 30.15mm, and the center thickness of the lens is 1.25mm. The distance between the second lens 2 and the first lens 1 is 40.7 mm, the distance between the fourth lens 4 and the third lens 3 is 0.30 mm, and the distance between the fifth lens 5 and the fourth lens 4 is 0.3 mm. The distance between the aperture and the sixth lens 6 is 14.3 mm, and the distance between the aperture and the seventh lens 7 is 2.31 mm.
[0033] The seventh lens 7 has a front surface curvature of 117.15 mm, a rear surface curvature radius of -45.16 mm, and a lens center thickness of 1.85 mm; the eighth lens 8 has a front surface curvature radius of infinity, a rear surface curvature radius of infinity, and a lens center thickness of 20 mm; the ninth lens 9 has a front surface curvature of -28.53 mm, a rear surface curvature radius of 32.69 mm, and a lens center thickness of 10 mm; the tenth lens 10 has a front surface curvature radius of -22.54 mm, a rear surface curvature radius of 238.65 mm, and a lens center thickness of 10 mm; the eleventh lens 11 has a front surface curvature radius of 238.65 mm, a rear surface curvature radius of -33.53 mm, and a lens center thickness of 7.78 mm; the twelfth lens 12 has a front surface curvature radius of -266.15 mm, a rear surface curvature radius of -129.4 mm, and a lens center thickness of 9.85 mm. The eighth lens 8 is spaced 11.1 mm from the seventh lens 7; the ninth lens 9 is spaced 10.3 mm from the eighth lens 8; the tenth lens 10 is spaced 16.3 mm from the ninth lens 9; the eleventh lens 11 is spaced 206.15 mm from the twelfth lens 12; and the distance from the twelfth lens 12 to the image plane is 14.13 mm.
[0034] The material of the first lens 1 is H-FK61B, and the effective aperture is Φ27.8mm; the material of the second lens 2 is H-ZLAF55D, and the effective aperture is Φ17.5mm; the material of the third lens 3 is H-FK61B, and the effective aperture is Φ18.5mm; the material of the fourth lens 4 is H-LAF50B, and the effective aperture is Φ20mm; the material of the fifth lens 5 is H-FK61B, and the effective aperture is Φ18mm; the material of the sixth lens 6 is H-ZLAF55D, and the effective aperture is Φ17.5mm. The seventh lens 7 is made of H-ZF5, with an effective aperture of Φ14.6mm; the eighth lens 8 is made of H-K9L, with an effective aperture of Φ20mm; the ninth lens 9 is made of H-FK61B, with an effective aperture of Φ17mm; the tenth lens 10 is made of H-F1, with an effective aperture of Φ24.4mm; the eleventh lens 11 is made of H-LAK51A, with an effective aperture of Φ36.5mm; the twelfth lens 12 is made of H-FK61B, with an effective aperture of Φ125mm.
[0035] The beneficial effects of the utility model are:
[0036] 1. Using large target surface imaging, the imaging inspection of large objects can be completed at one time to improve inspection efficiency and save costs;
[0037] 2. It can improve the magnification, especially for the inspection of small objects, to see more subtle problems, especially in AOI inspection to avoid major quality problems, expand the scope of application and use efficiency;
[0038] 3. It not only has the advantage of large target imaging, but also can meet the requirements of high resolution for details. The design concept of telecentric lens and diffraction limit makes the brightness and resolution of the whole picture uniform, and reduces the alignment error and reading error, thus improving the accuracy.
[0039] 4. The coaxial system with Kohler illumination can reduce the dependence on external light and the requirements for complex environments, improve the brightness of the object surface and make the brightness of the imaging surface more uniform, avoiding the phenomenon of inconsistent brightness of the picture.
[0040] The diameter of the lenses in the rear optical group is getting larger and larger to meet the needs of large field of view and large target imaging. The number of lenses in the entire system reaches twelve in order to eliminate various aberrations to improve resolution requirements; secondly, the aperture is set in the middle part of the optical system to achieve ultra-high resolution and uniform image surface, thereby realizing the large magnification and high resolution of the lens.
[0041] It should be noted that the Kohler illumination system includes a light source, a Kohler lens 13, a field stop, an aperture stop and a condenser lens 14 arranged in sequence along the light direction; the light source is selected to be a white light source with controllable brightness, the Kohler lens 13 is a double meniscus convex lens which can magnify and converge the filament image of the light source, there is a field stop behind the Kohler lens 13 which can be used to adjust the brightness of the light source, an aperture stop is arranged behind the field stop, and a condenser lens 14 is arranged behind the aperture stop, wherein The position plane of the aperture diaphragm is the front focal plane of the condenser lens 14. When all the light points of the light source luminous body converge on the aperture diaphragm of the condenser lens 14, a complete image of the luminous body is formed, and the illumination light emitted from the condenser lens 14 is a beam of parallel light converged from all the light points on the luminous body from all directions, which will make the object fully illuminated. This kind of illumination is provided to the main imaging lens and the object surface, thereby improving the brightness and uniformity of the imaging surface, thereby achieving the goal of improving the brightness of the picture and the uniformity of high resolution.
[0042] like Figure 3 As shown in the figure, it can be seen that the MTF curve is very concentrated and will not cause differences in resolution in different fields of view, thereby ensuring that the image resolution of the entire large target surface is uniform.
[0043] like Figure 4 As shown in the figure, it can be seen from the point diagram that the imaging points of different colors of light in different fields of view are very small, and there is no obvious aberration drift.
[0044] like Figure 5 As shown, there is no filament image in the effective area of Köhler illumination, and the illumination is uniform throughout the entire illumination area. The light at the edge can be eliminated by adjusting the field diaphragm and aperture diaphragm and will not participate in the illumination of the object and the imaging range.
[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A telecentric lens with coaxial light and Kohler illumination, characterized in that: The coaxial optical target telecentric lens comprises a housing, a front optical group and a rear optical group arranged in the housing, an aperture arranged between the front optical group and the rear optical group, and a Kohler illumination assembly arranged in the housing, wherein the front optical group comprises 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) arranged in sequence along the optical axis, and the rear optical group comprises a seventh lens (7), an eighth lens (8), a ninth lens (9), a tenth lens (10), an eleventh lens (11) and a twelfth lens (12) arranged in sequence along the optical axis; the Kohler illumination assembly is arranged on the side of the eighth lens (8), and the light of the Kohler illumination assembly is perpendicular to the optical axis; Wherein, the second lens (2) and the third lens (3) are combined into a first cemented lens, the fifth lens (5) and the sixth lens (6) are combined into a second cemented lens, the aperture is located between the sixth lens (6) and the seventh lens (7), and the tenth lens (10) and the eleventh lens (11) are combined into a third cemented lens; The first lens (1), the third lens (3), the fourth lens (4) and the fifth lens (5) are all biconvex lenses, the second lens (2) and the sixth lens (6) are all biconcave lenses, the seventh lens (7), the eleventh lens (11) and the twelfth lens (12) are all negative meniscus lenses, the eighth lens (8) is a cylindrical lens or a right-angle prism; the ninth lens (9) is a biconcave lens, and the tenth lens (10) is a positive meniscus lens.
2. The telecentric lens with coaxial light and Kohler illumination according to claim 1, characterized in that: The first lens (1) has a front surface curvature of 52.088 mm, a rear surface curvature radius of -85.662 mm, and a lens center thickness of 3.9 mm; the second lens (2) has a front surface curvature radius of -22.95 mm, a rear surface curvature radius of 29.23 mm, and a lens center thickness of 1.3 mm; the third lens (3) has a front surface curvature radius of -22.95 mm, a rear surface curvature radius of -29.95 mm, and a lens center thickness of 3.86 mm; The front surface curvature radius of the fourth lens (4) is 36.03 mm, the rear surface curvature radius is -34.26 mm, and the center thickness of the lens is 5.13 mm; the front surface curvature radius of the fifth lens (5) is 31.49 mm, the rear surface curvature radius is -26.97 mm, and the center thickness of the lens is 3.6 mm; the front surface curvature radius of the sixth lens (6) is -26.97 mm, the rear surface curvature radius is 30.15 mm, and the center thickness of the lens is 1.25 mm.
3. The telecentric lens with coaxial light and Kohler illumination according to claim 2, characterized in that: The distance between the second lens (2) and the first lens (1) is 40.7 mm; the distance between the fourth lens (4) and the third lens (3) is 0.30 mm; and the distance between the fifth lens (5) and the fourth lens (4) is 0.3 mm.
4. The telecentric lens with coaxial light and Kohler illumination according to claim 1, characterized in that: The distance between the aperture and the sixth lens (6) is 14.3 mm, and the distance between the aperture and the seventh lens (7) is 2.31 mm.
5. The telecentric lens with coaxial light and Kohler illumination according to claim 1, characterized in that: The seventh lens (7) has a front surface curvature of 117.15 mm, a rear surface curvature radius of -45.16 mm, and a lens center thickness of 1.85 mm; the eighth lens (8) has a front surface curvature radius of infinity, a rear surface curvature radius of infinity, and a lens center thickness of 20 mm; the ninth lens (9) has a front surface curvature of -28.53 mm, a rear surface curvature radius of 32.69 mm, and a lens center thickness of 10 mm; the tenth lens (10) has a front surface curvature of -28.53 mm, a rear surface curvature radius of 32.69 mm, and a lens center thickness of 10 mm. The surface curvature radius is -22.54mm, the curvature radius of the rear surface is 238.65mm, and the center thickness of the lens is 10mm; the front surface curvature radius of the eleventh lens (11) is 238.65mm, the curvature radius of the rear surface is -33.53mm, and the center thickness of the lens is 7.78mm; the front surface curvature radius of the twelfth lens (12) is -266.15mm, the curvature radius of the rear surface is -129.4mm, and the center thickness of the lens is 9.85mm.
6. The telecentric lens with coaxial light and Kohler illumination according to claim 5, characterized in that: The distance between the eighth lens (8) and the seventh lens (7) is 11.1 mm; the distance between the ninth lens (9) and the eighth lens (8) is 10.3 mm; the distance between the tenth lens (10) and the ninth lens (9) is 16.3 mm; the distance between the eleventh lens (11) and the twelfth lens (12) is 206.15 mm; and the distance between the twelfth lens (12) and the image plane is 14.13 mm.
7. The telecentric lens with coaxial light and Kohler illumination according to claim 1, characterized in that: The material of the first lens (1) is H-FK61B, and the effective aperture is Φ27.8mm; the material of the second lens (2) is H-ZLAF55D, and the effective aperture is Φ17.5mm; the material of the third lens (3) is H-FK61B, and the effective aperture is Φ18.5mm; the material of the fourth lens (4) is H-LAF50B, and the effective aperture is Φ20mm; the material of the fifth lens (5) is H-FK61B, and the effective aperture is Φ18mm; the material of the sixth lens (6) is H-ZLAF55D, and the effective aperture is Φ17.5mm.
8. The telecentric lens with coaxial light and Kohler illumination according to claim 1, characterized in that: The seventh lens (7) is made of H-ZF5, with an effective aperture of Φ14.6 mm; the eighth lens (8) is made of H-K9L, with an effective aperture of Φ20 mm; the ninth lens (9) is made of H-FK61B, with an effective aperture of Φ17 mm; the tenth lens (10) is made of H-F1, with an effective aperture of Φ24.4 mm; the eleventh lens (11) is made of H-LAK51A, with an effective aperture of Φ36.5 mm; the twelfth lens (12) is made of H-FK61B, with an effective aperture of Φ125 mm.