Coaxial imaging optical system and optical equipment in high-energy laser
By optimizing the lens combination of the high-energy laser imaging optical system, the problems of astigmatism and on-axis chromatic aberration were solved, achieving efficient imaging results and a low failure rate.
Patent Information
- Application Number
- CN202423171254.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-12-23
AI Technical Summary
Existing high-energy laser imaging optical paths produce significant astigmatism and on-axis chromatic aberration in the 650nm-1070nm wavelength range, resulting in poor image quality.
Design a coaxial imaging optical system within a high-energy laser, comprising a main lens group, a compensating plane mirror, and five lens groups. Optimize parameters such as the refractive index, Abbe number, and radius of curvature of the lenses, and combine simulation results to optimize coma, astigmatism, and on-axis chromatic aberration.
It effectively optimizes coma, astigmatism, and on-axis chromatic aberration, improving imaging quality while reducing workload and failure rate.
Smart Images
Figure CN223539071U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical system technology, and in particular to a coaxial imaging optical system and optical device in high-energy lasers. Background Technology
[0002] A coaxial telecentric lens is an optical element whose primary function is to magnify images and improve resolution. It consists of multiple lenses, each with its optical center aligned on a straight line, resulting in a sharper and clearer image. Coaxial telecentric lenses are widely used in medical, industrial, and military fields. The design and manufacture of coaxial telecentric lenses require advanced optical technology and sophisticated craftsmanship. Each lens needs to be processed and adjusted to ensure perfect alignment of their positions and angles, resulting in a distortion-free image. Furthermore, coaxial telecentric lenses must possess high stability and durability to withstand various harsh environments and operating conditions.
[0003] To address the complex lighting challenges commonly encountered in industrial inspection, coaxial telecentric lenses are often used in conjunction with specialized ring or coaxial light sources. This lighting design reduces shadows and highlights, ensuring uniform illumination of the surface of the object being inspected, thereby improving the stability and reliability of the inspection. Especially in imaging reflective or light-absorbing materials, a well-designed lighting scheme combined with the characteristics of a coaxial telecentric lens can significantly improve the accuracy and efficiency of the inspection.
[0004] like Figure 1 The diagram shows a schematic of a high-energy laser imaging optical path in the prior art. Based on the Seidel coefficient evaluation of the optical path, its field curvature (0.000289) and distortion (0.000009) are relatively small. However, this optical path produces huge astigmatism and on-axis chromatic aberration for light in the 650nm-1070nm wavelength band, resulting in poor imaging quality for common cameras. Therefore, this invention develops a coaxial imaging optical system and optical device within a high-energy laser to solve the problems existing in the prior art. Utility Model Content
[0005] The purpose of this invention is to provide a coaxial imaging optical system and optical device within a high-energy laser to solve the problem of poor imaging effect in the existing optical path.
[0006] The technical solution of this utility model is: a coaxial imaging optical system in high-energy laser, comprising a main lens group, a compensation plane mirror, and five lens groups arranged sequentially along the optical path;
[0007] The main lens group includes a first main lens, a second main lens, and a third main lens;
[0008] The five sets of lenses include:
[0009] The first lens is a concave mirror with negative refractive power;
[0010] The second lens is a convex mirror with positive refractive power;
[0011] The third lens is a cemented lens, comprising a front lens and a rear lens; the front lens is a concave mirror with negative refractive power, and the rear lens is a convex mirror with positive refractive power.
[0012] The fourth lens is a concave mirror with negative refractive power;
[0013] The fifth lens is a convex mirror with positive refractive power;
[0014] The refractive indices and Abbe numbers among the five lens groups satisfy the following relationship:
[0015] 1<nd / nd i<1.25; i=1, 2, 31, 32, 4, 5;
[0016] Wherein, nd is the refractive index of the compensating plane mirror;
[0017] nd1, nd2, nd4, and nd5 are the refractive indices of the first, second, fourth, and fifth lenses, respectively; nd31 is the refractive index of the front lens; and nd32 is the refractive index of the rear lens.
[0018] 1.3<vd / vd i<2.56; i=1, 2, 31, 32, 4, 5;
[0019] Where vd is the Abbe number of the compensating plane mirror;
[0020] vd1, vd2, vd4, and vd5 are the Abbe numbers of the first, second, fourth, and fifth lenses, respectively; vd31 is the Abbe number of the front lens; and vd32 is the Abbe number of the rear lens.
[0021] Preferably, among the five lens groups, the radii of curvature of the first lens, the front lens, the rear lens, and the fifth lens along the incident and exit ends of the optical path satisfy the following relationship:
[0022] 1.2<|(R i+R i') / (R iR i')|<2.4, i=1, 31, 32, 5;
[0023] The relationship between the radii of curvature of the second lens at the incident and exit ends along the optical path is as follows:
[0024] 0.5<|(R2+R2') / (R2-R2')|<1;
[0025] The relationship between the radii of curvature of the fourth lens at the incident and exit ends along the optical path is as follows:
[0026] 4.8<|(R4+R4') / (R4-R4')|<5;
[0027] Where Ri is the radius of curvature at the incident end, and Ri' is the radius of curvature at the exit end.
[0028] Preferably, the thickness H of the compensating plane mirror satisfies: 7 < H < 7.5 mm;
[0029] Among the five sets of lenses, the central thickness of each concave mirror satisfies the following relationship:
[0030] 2.6<H / hi<7.2; i=1, 31, 4;
[0031] Among the five sets of lenses, the central thickness of each convex mirror satisfies the following relationship:
[0032] 0.4<H / hi<0.85; i=2, 32, 5;
[0033] Among them, h1, h2, h31, h32, h4, and h5 are the center thicknesses of the first lens, the second lens, the front lens, the rear lens, the fourth lens, and the fifth lens, respectively.
[0034] Preferably, the second lens and the third lens constitute a lens group, and the air gap between the second lens and the third lens is 1mm ± 5%.
[0035] Preferably, the fourth lens and the fifth lens constitute a lens group, and the air gap between the fourth lens and the fifth lens is 1.6mm + 5%.
[0036] Preferably, in the main lens group, the first main lens is a convex mirror, the second main lens is a concave mirror, and the third main lens is a reflecting mirror.
[0037] Preferably, the radii of curvature of the first main lens at the incident end and the exit end along the optical path satisfy the following relationship:
[0038] -0.2 < Rz1 / Rz1' < -0.1;
[0039] The relationship between the radii of curvature of the second main lens at the incident end and the exit end along the optical path is as follows:
[0040] 0.9 < Rz2 / Rz2' < 1;
[0041] Wherein, Rz1 is the radius of curvature of the first main lens at the incident end of the light path, and Rz1' is the radius of curvature of the first main lens at the exit end of the light path; Rz2 is the radius of curvature of the second main lens at the incident end of the light path, and Rz2' is the radius of curvature of the second main lens at the exit end of the light path.
[0042] Preferably, the surface of the third main lens is coated.
[0043] This application also discloses an optical device, including the coaxial imaging optical system in a high-energy laser as described above.
[0044] Compared with the prior art, the advantages of this utility model are:
[0045] (1) This application is used to install in a high-energy laser system and is coaxial with the emission optical path. Compared with the external dimming axis of the camera, the coaxial optical path greatly reduces the workload and failure rate. By adding a compensation plane mirror and five sets of lenses after the traditional main lens group, it can be seen from the simulation results that it effectively optimizes coma, astigmatism and on-axis chromatic aberration, and has a good imaging effect.
[0046] (2) A compensating plane mirror is set between the main lens group and the five lens groups. Since the dispersion in the X and Y directions of the front optical path corresponding to the main lens group is quite different, the compensating plane mirror is added to make the dispersion in the X and Y directions more consistent. Attached Figure Description
[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0048] Figure 1 This is a schematic diagram of the main lens assembly in the prior art;
[0049] Figure 2 This is a structural diagram of a coaxial imaging optical system within a high-energy laser according to the present invention.
[0050] Figure 3 This is an MTF curve of a coaxial imaging optical system within a high-energy laser according to the present invention.
[0051] Among them: 1. Main lens group;
[0052] 11. First main lens; 12. Second main lens; 13. Third main lens;
[0053] 2. Compensating plane mirror;
[0054] 3. Five groups of lenses;
[0055] 31. First lens; 32. Second lens; 33. Third lens; 331. Front lens; 332. Rear lens; 34. Fourth lens; 35. Fifth lens. Detailed Implementation
[0056] The present invention will be further described in detail below with reference to specific embodiments:
[0057] A coaxial imaging optical system within a high-energy laser includes a main lens group 1, a compensation plane mirror 2, and five lens groups 3 arranged sequentially along the optical path.
[0058] Regarding main lens group 1:
[0059] like Figure 1 As shown, the main lens group 1 includes a first main lens 11, a second main lens 12 and a third main lens 13; the first main lens 11 is a convex mirror, the second main lens 12 is a concave mirror and the third main lens 13 is a reflecting mirror.
[0060] The relationship between the radii of curvature of the first main lens at the incident end and the exit end along the optical path is as follows:
[0061] -0.2 < Rz1 / Rz1' < -0.1;
[0062] The relationship between the radii of curvature of the second main lens at the incident and exit ends along the optical path is as follows:
[0063] 0.9 < Rz2 / Rz2' < 1;
[0064] Wherein, Rz1 is the radius of curvature of the first main lens at the incident end of the light path, and Rz1' is the radius of curvature of the first main lens at the exit end of the light path; Rz2 is the radius of curvature of the second main lens at the incident end of the light path, and Rz2' is the radius of curvature of the second main lens at the exit end of the light path.
[0065] Specifically, in this embodiment, the first main lens is made of C7980, the radius of curvature of the first main lens at the incident end of the optical path is 180.370 mm, and the radius of curvature of the first main lens at the exit end of the optical path is -908.270 mm.
[0066] The second main lens is made of C7980 material. The radius of curvature of the second main lens at the incident end of the light path is -141.538mm, and the radius of curvature at the exit end of the light path is -154.678mm.
[0067] The third main lens is made of SAPPH I RE, which has a low thermal absorption coefficient and produces little deformation at high temperatures. The third main lens is a high-intensity reflector with a coating on its surface. The coating has a reflectivity of 99.99% for light with a wavelength of 1070nm and a transmittance of more than 80% for light in the visible light band.
[0068] In the main lenses, the center thickness of the first main lens is 12mm, the center thickness of the second main lens is 11.938mm, and the thickness of the third main lens is 7mm. The air gap between the first and second main lenses is 5mm, and the air gap between the second and third main lenses is 82.058mm.
[0069] Regarding compensating plane mirror 2:
[0070] The main reason is that the dispersion in the X and Y directions of the front optical path corresponding to the main lens group 1 is quite different. The addition of the compensating plane mirror 2 makes the dispersion in the X and Y directions more consistent.
[0071] The thickness of the compensating plane mirror is 7.17 mm, and its refractive index and Abbe number satisfy the following ranges:
[0072] 1.4<nd<1.6, 92.5<vd<96.
[0073] In this embodiment, the compensating plane mirror is made of H-FK95N material.
[0074] Regarding the five groups of lenses 3:
[0075] like Figure 2 As shown, the five lens groups 3 include a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, and a fifth lens 35.
[0076] The first lens 31 is a concave mirror with negative refractive power; the second lens 32 is a convex mirror with positive refractive power; the third lens 33 is a cemented lens, including a front lens 331 and a rear lens 332; the front lens 331 is a concave mirror with negative refractive power and the rear lens 332 is a convex mirror with positive refractive power; the fourth lens 34 is a concave mirror with negative refractive power; and the fifth lens 35 is a convex mirror with positive refractive power.
[0077] The refractive indices of the five lens groups satisfy the following relationship:
[0078] 1<nd / nd i<1.25; i=1, 2, 31, 32, 4, 5;
[0079] Where nd is the refractive index of the compensating plane mirror;
[0080] nd1, nd2, nd4, and nd5 are the refractive indices of the first, second, fourth, and fifth lenses, respectively; nd31 is the refractive index of the front lens; and nd32 is the refractive index of the rear lens.
[0081] More specifically, 1.1 < nd / nd1 < 1.15.
[0082] 1.05 < nd / nd2 < 1.15
[0083] 1.1 < nd / nd31 < 1.15,
[0084] 1.05 < nd / nd32 < 1.15
[0085] 1.1 < nd / nd4 < 1.2,
[0086] 1.2 < nd / nd5 < 1.3.
[0087] The Abbe numbers among the five lens groups satisfy the following relationship:
[0088] 1.3<vd / vd i<2.56; i=1, 2, 31, 32, 4, 5;
[0089] Where vd is the Abbe number of the compensating plane mirror;
[0090] vd1, vd2, vd4, and vd5 are the Abbe numbers of the first, second, fourth, and fifth lenses, respectively; vd31 is the Abbe number of the front lens; and vd32 is the Abbe number of the rear lens.
[0091] More specifically, 1.5 < vd / vd1 < 1.65.
[0092] 1.3 < vd / vd2 < 1.4
[0093] 2 < vd / vd31 < 2.2,
[0094] 1.3 < vd / vd32 < 1.4
[0095] 2.5 < vd / vd4 < 2.56
[0096] 1.8 < vd / vd5 < 2.
[0097] Since refractive index and Abbe number are material specifications and are determined by the specific lens material, in this embodiment, the first lens is made of H-LAK4L; the second and rear lenses are made of the same material, H-ZPK7; the front lens is made of H-TF3L; the fourth lens is made of H-F2; and the fifth lens is made of H-LAF50B.
[0098] Among the five lens groups, the radii of curvature of the first lens, the front lens, the rear lens, and the fifth lens along the incident and exit ends of the light path satisfy the following relationship:
[0099] 1.2<|(R i+R i') / (R iR i')|<2.4, i=1, 31, 32, 5;
[0100] The relationship between the radii of curvature of the second lens at the incident and exit ends along the optical path is as follows:
[0101] 0.5<|(R2+R2') / (R2-R2')|<1;
[0102] The relationship between the radii of curvature of the fourth lens at the incident and exit ends along the optical path is as follows:
[0103] 4.8<|(R4+R4') / (R4-R4')|<5;
[0104] Where Ri is the radius of curvature at the incident end, and Ri' is the radius of curvature at the exit end.
[0105] More specifically, in this embodiment, the radii of curvature of the five lens groups are as shown in Table 1 below:
[0106] Table 1. Radius of curvature of each lens in the five lens groups at the incident and exit points along the light path
[0107] lens Radius of curvature at the incident end (mm) Radius of curvature at the exit end (mm) First lens 169.469 43.791 Second lens 255.241 -83.985 Front lens 168.395 36.04 Rear lens 36.04 88.456 Fourth lens 91.622 39.661 Fifth lens 41.562 353.572
[0108] In the five sets of lenses, the central thickness of each concave mirror satisfies the following relationship:
[0109] 2.6<H / hi<7.2; i=1, 31, 4;
[0110] In the five sets of lenses, the central thickness of each convex mirror satisfies the following relationship:
[0111] 0.4<H / hi<0.85; i=2, 32, 5;
[0112] Among them, h1, h2, h31, h32, h4, and h5 are the center thicknesses of the first lens, the second lens, the front lens, the rear lens, the fourth lens, and the fifth lens, respectively.
[0113] More specifically, in this embodiment, the center thickness of the five lens groups is as shown in Table 2 below:
[0114] Table 2. Center thickness of each lens in the five lens groups
[0115] lens Center thickness (mm) First lens 1.425 Second lens 8.659 Front lens 1 Rear lens 11.34 Fourth lens 2.663 Fifth lens 15
[0116] The second and third lenses form a lens group, with an air gap of 1 mm ± 5% between them. The fourth and fifth lenses form a lens group, with an air gap of 1.6 mm + 5% between them.
[0117] In this embodiment, the air gap between the second lens and the third lens is 1 mm, and the air gap between the fourth lens and the fifth lens is 1.665 mm.
[0118] The Seidel coefficient evaluation of the optical path of the coaxial imaging optical system within a high-energy laser based on this application is shown in Table 3 below:
[0119] Table 3. Evaluation of Seidel coefficients
[0120] Seidel coefficient Ball difference 0.001239 coma 0.000068 Like scattered -0.000023 Field music 0.000397 distortion 0.002148 On-axis color difference 0.000399 Vertical color difference 0.000335
[0121] Combined Figure 3 The MTF curve shown demonstrates that by adding a compensating plane mirror and five other lenses after the traditional main lens group, and combining the simulation results, the deviations in coma, astigmatism, and on-axis chromatic aberration are relatively small, resulting in significant optimization and good imaging performance.
[0122] Based on the above, this application also discloses an optical device, including the aforementioned coaxial imaging optical system within a high-energy laser. This application can be installed within a high-energy laser system, coaxial with the emitting optical path. Compared to an external adjustment axis for a camera, the coaxial optical path significantly reduces workload and failure rate.
[0123] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and therefore, all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this utility model.
Claims
1. A coaxial imaging optical system within a high-energy laser, characterized in that, It includes a main lens group, a compensating plane mirror, and five lens groups arranged sequentially along the optical path. The main lens group includes a first main lens, a second main lens, and a third main lens; The five sets of lenses include: The first lens is a concave mirror with negative refractive power; The second lens is a convex mirror with positive refractive power; The third lens is a cemented lens, comprising a front lens and a rear lens; the front lens is a concave mirror with negative refractive power, and the rear lens is a convex mirror with positive refractive power. The fourth lens is a concave mirror with negative refractive power; The fifth lens is a convex mirror with positive refractive power; The refractive indices and Abbe numbers among the five lens groups satisfy the following relationship: 1<nd / ndi<1.25; i=1, 2, 31, 32, 4, 5; Wherein, nd is the refractive index of the compensating plane mirror; nd1, nd2, nd4, and nd5 are the refractive indices of the first, second, fourth, and fifth lenses, respectively; nd31 is the refractive index of the front lens; and nd32 is the refractive index of the rear lens. 1.3<vd / vdi<2.56; i=1, 2, 31, 32, 4, 5; Where vd is the Abbe number of the compensating plane mirror; vd1, vd2, vd4, and vd5 are the Abbe numbers of the first, second, fourth, and fifth lenses, respectively; vd31 is the Abbe number of the front lens; and vd32 is the Abbe number of the rear lens.
2. The coaxial imaging optical system within a high-energy laser according to claim 1, characterized in that: Among the five sets of lenses, the radii of curvature of the first lens, the front lens, the rear lens, and the fifth lens along the incident and exit ends of the optical path satisfy the following relationship: 1.2<|(Ri+Ri') / (Ri-Ri')|<2.4, i=1, 31, 32, 5; The relationship between the radii of curvature of the second lens at the incident and exit ends along the optical path is as follows: 0.5<|(R2+R2') / (R2-R2')|<1; The relationship between the radii of curvature of the fourth lens at the incident and exit ends along the optical path is as follows: 4.8<|(R4+R4') / (R4-R4')|<5; Where Ri is the radius of curvature at the incident end and Ri' is the radius of curvature at the exit end.
3. The coaxial imaging optical system within a high-energy laser according to claim 2, characterized in that: The thickness H of the compensating plane mirror satisfies: 7 < H < 7.5 mm; Among the five sets of lenses, the central thickness of each concave mirror satisfies the following relationship: 2.6<H / hi<7.2; i=1, 31, 4; Among the five sets of lenses, the central thickness of each convex mirror satisfies the following relationship: 0.4<H / hi<0.85; i=2, 32, 5; Among them, h1, h2, h31, h32, h4, and h5 are the center thicknesses of the first lens, the second lens, the front lens, the rear lens, the fourth lens, and the fifth lens, respectively.
4. The coaxial imaging optical system within a high-energy laser according to claim 3, characterized in that: The second lens and the third lens form a lens group, and the air gap between the second lens and the third lens is 1mm ± 5%.
5. The coaxial imaging optical system within a high-energy laser according to claim 3, characterized in that: The fourth lens and the fifth lens form a lens group, and the air gap between the fourth lens and the fifth lens is 1.6mm + 5%.
6. The coaxial imaging optical system within a high-energy laser according to claim 1, characterized in that: In the main lens group, the first main lens is a convex mirror, the second main lens is a concave mirror, and the third main lens is a reflecting mirror.
7. The coaxial imaging optical system within a high-energy laser according to claim 6, characterized in that: The relationship between the radii of curvature of the first main lens at the incident end and the exit end along the optical path is as follows: -0.2 < Rz1 / Rz1' < -0.1; The relationship between the radii of curvature of the second main lens at the incident end and the exit end along the optical path is as follows: 0.9 < Rz2 / Rz2' < 1; Wherein, Rz1 is the radius of curvature of the first main lens at the incident end of the light path, and Rz1' is the radius of curvature of the first main lens at the exit end of the light path; Rz2 is the radius of curvature of the second main lens at the incident end of the light path, and Rz2' is the radius of curvature of the second main lens at the exit end of the light path.
8. A coaxial imaging optical system within a high-energy laser according to claim 6, characterized in that: The surface of the third main lens is coated.
9. An optical device, characterized in that: The invention includes a coaxial imaging optical system within a high-energy laser as described in any one of claims 1-8.