Fixed-focus high-definition infrared confocal large-target-surface imaging optical system
By designing a fixed-focus high-definition infrared confocal large target imaging optical system, using a combination of meniscus lenses and cemented lenses, and an achromatic design, a large target area and high-resolution imaging at a focal length of 50mm is achieved, solving the problem of insufficient high-definition imaging in existing security lenses.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CRYLIGHT PHOTONICS INC
- Filing Date
- 2025-05-26
- Publication Date
- 2026-04-21
AI Technical Summary
Existing security lenses have a small target area at a focal length of 50mm, insufficient infrared confocal capability, and insufficient resolution, which cannot meet the high-definition imaging requirements of fields such as smart homes and facial recognition.
A fixed-focus, high-definition infrared confocal large-target imaging optical system is designed, employing eleven optical spherical lenses, including meniscus lenses, biconcave lenses, and biconvex lenses. A large-angle light is limited by an aperture stop, and three sets of cemented lens groups are set to eliminate chromatic aberration. Ultra-low dispersion glass material is used to achieve a large aperture, large resolution, and high resolution.
Achieves 1' full-field equivalent image quality at a focal length of 50mm, with a resolution of 12MP, excellent infrared clarity, short overall system length, strong chromatic aberration capability, and high image clarity.
Smart Images
Figure CN224152739U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical imaging equipment technology, specifically to a fixed-focus high-definition infrared confocal large target surface imaging optical system. Background Technology
[0002] As people's living standards improve, they have higher demands for compact, lightweight, and high-definition lenses used in smart homes, facial recognition, and mobile security. Existing security lenses have small target surfaces, insufficient infrared confocal capabilities, and inadequate resolution at a 50mm focal length. Summary of the Invention
[0003] The technical problem to be solved by this utility model is to provide a fixed-focus high-definition infrared confocal large target imaging optical system, which can achieve the same image quality across the entire field of view of the target surface at a focal length of 50mm, and the resolution can reach 12MP, with outstanding overall performance.
[0004] This utility model is implemented as follows:
[0005] A fixed-focus, high-definition infrared confocal large-target imaging optical system is characterized by comprising, from the object plane to the image plane, a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens; wherein the first, second, third, and sixth lenses are meniscus lenses, and the fourth and eleventh lenses are biconcave lenses; the fifth, seventh, and ninth lenses are biconvex lenses, and the tenth lens is a plano-convex lens; the second and third lenses are combined to form a first cemented lens, the fourth and fifth lenses are combined to form a second cemented lens, and the sixth, seventh, and eighth lenses are combined to form a third cemented lens; the aperture stop is positioned between the third and fourth lenses at the front end of the system, restricting large-angle light rays converged by the positive meniscus lens and the cemented lens group in front of the aperture stop, and a set of cemented lenses is set at each end of the aperture stop, achieving good achromatic effect through a symmetrical structure.
[0006] Furthermore, the air gap between the first lens and the first cemented lens is 0.1≤D1≤0.5, the air gap between the first cemented lens and the aperture stop is 10≤D2≤15, the air gap between the aperture stop and the second cemented lens is 0.5≤D3≤3, the air gap between the second cemented lens and the third cemented lens is 5≤D4≤9, the air gap between the third cemented lens and the ninth lens is 0.1≤D5≤0.5, the air gap between the ninth lens and the tenth lens is 0.5≤D6≤3, and the air gap between the tenth lens and the eleventh lens is 10≤D7≤15.
[0007] Furthermore, the curvatures of the eleven optical spherical lenses satisfy the following relationship:
[0008] First lens: 30≤R1≤38 100≤R2≤107
[0009] Second lens: 22≤R1≤29 152≤R2≤158
[0010] Third lens: 152≤R1≤158 12≤R2≤18
[0011] Fourth lens: -32≤R1≤-26 15≤R2≤20
[0012] Fifth lens: 15≤R1≤20 -58≤R2≤-52
[0013] Sixth lens: 107≤R1≤115 15≤R2≤20
[0014] Seventh lens: 15≤R1≤20 -18≤R2≤-12
[0015] Eighth lens: -18≤R1≤-12 -68≤R2≤-62
[0016] Ninth lens: 39≤R1≤44 -44≤R2≤-38
[0017] Tenth lens: 32≤R1≤38R2=0
[0018] Eleventh lens: -48≤R1≤-41 15≤R2≤20
[0019] Where R1 is the curvature of the object side surface and R2 is the curvature of the image side surface.
[0020] Furthermore, the first lens has a refractive index of 1.8 and an Abbe number of 37.2; the second lens has a refractive index of 1.4 and an Abbe number of 90.2; the third lens has a refractive index of 1.6 and an Abbe number of 37.3; the fourth lens has a refractive index of 1.6 and an Abbe number of 42.6; the fifth lens has a refractive index of 1.8 and an Abbe number of 35.1; the sixth lens has a refractive index of 1.5 and an Abbe number of 60.1; the seventh lens has a refractive index of 1.4 and an Abbe number of 90.2; the eighth lens has a refractive index of 1.6 and an Abbe number of 34.7; the ninth lens has a refractive index of 1.8 and an Abbe number of 62.6; the tenth lens has a refractive index of 1.8 and an Abbe number of 42.7; and the eleventh lens has a refractive index of 1.5 and an Abbe number of 68.9.
[0021] Furthermore, the first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, the fifth lens has positive optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has positive optical power, and the eleventh lens has negative optical power.
[0022] Preferably, at least two of the first cemented lens, the second cemented lens, and the third cemented lens are made of ultra-low dispersion glass.
[0023] Preferably, the Abbe number of the ultra-low dispersion glass is 94.5.
[0024] This utility model has the following advantages:
[0025] The first three lenses of the optical system are meniscus lenses, capable of converging light rays at a wider angle into the system, achieving a large aperture. The aperture stop is positioned between the third and fourth lenses at the front of the system, restricting the large-angle light rays converged by the positive meniscus lens and cemented lens group in front of the aperture stop, effectively reducing aberrations and improving sharpness. A set of cemented doublet lenses is placed at each end of the aperture stop, using a symmetrical structure to achieve good achromatic effect and improve infrared confocal sharpness. The system uses a total of three cemented lens groups, including two sets of cemented doublet lenses and one set of cemented triplet lenses, effectively reducing the overall system length while providing strong achromatic capability, thus improving the system's imaging sharpness. This results in an optical system with a focal length of 50mm ± 5%, image quality matching the full field of view at 1', excellent infrared sharpness, a resolution of 12MP, and an aperture of f / 1.5.
[0026] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description
[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0028] Figure 1 This is a schematic diagram of the optical system of this utility model;
[0029] Figure 2 This is a standard dot diagram of the optical system according to an embodiment of the present invention;
[0030] Figure 3 This is a schematic diagram of the field curvature and distortion of the optical system in an embodiment of this utility model;
[0031] Figure 4 This is a graph showing the modulation transfer function of an embodiment of the present invention;
[0032] Figure 5 This is one of the ray fan diagrams of this utility model embodiment;
[0033] Figure 6 This is the second optical fan diagram of an embodiment of this utility model;
[0034] Figure 7 This is the third optical fan diagram of an embodiment of this utility model;
[0035] Figure 8 This is the fourth optical fan diagram of an embodiment of this utility model;
[0036] Figure 9 This is the fifth optical fan diagram of the present invention;
[0037] Figure 10 This is the sixth optical fan diagram of an embodiment of this utility model. Detailed Implementation
[0038] This utility model provides a fixed-focus high-definition infrared confocal large target imaging optical system, which can achieve the same image quality across the entire field of view of the target surface at a focal length of 50mm, and the resolution can reach 12MP, with outstanding overall performance.
[0039] The overall concept of the technical solution in this embodiment of the utility model is as follows:
[0040] The first three lenses of the optical system are meniscus lenses, capable of converging light at a wider angle into the system, achieving a large aperture. The aperture stop is positioned between the third and fourth lenses at the front of the system, restricting the large-angle light rays converged by the positive meniscus lens and cemented lens group in front of the aperture stop, effectively reducing aberrations and improving sharpness. A set of cemented doublet lenses is placed at each end of the aperture stop, using a symmetrical structure to achieve good achromatic effect and improve infrared confocal sharpness. The system uses a total of three cemented lens groups, including two sets of cemented doublet lenses and one set of cemented triplet lenses, effectively reducing the overall system length while providing strong achromatic capability, thus improving system imaging sharpness. The last lens is a negative power biconcave lens, diverging light to achieve a large target surface. At least two of the three cemented components are made of ultra-low dispersion glass with an Abbe number of 94.5, effectively reducing system chromatic aberration and improving infrared sharpness. The system employs a positive-positive-negative-positive-negative-positive-positive-negative optical power combination, which can achieve a system focal length of 50mm ± 5%, an image quality that meets the requirements of a 1' full field of view, excellent infrared clarity, a resolution of 12MP, and an aperture of f / 1.5.
[0041] Based on the above-described inventive concept, this embodiment provides a fixed-focus, high-definition infrared confocal large-target-area imaging optical system, such as... Figure 1As shown, from the object plane to the image plane, the lens comprises, in sequence, a first lens 1, a second lens 2, a third lens 3, an aperture stop 12, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, and an eleventh lens 11; wherein, the first lens 1, the second lens 2, the third lens 3, and the sixth lens 6 are meniscus lenses, the fourth lens 4 and the eleventh lens 11 are biconcave lenses; the fifth lens 5, the seventh lens 7, and the ninth lens 9 are biconvex lenses, and the tenth lens 10 is a plano-convex lens; the second lens 2 and the third lens 3 are combined to form a first cemented lens, the fourth lens 4 and the fifth lens 5 are combined to form a second cemented lens, and the sixth lens 6, the seventh lens 7, and the eighth lens 8 are combined to form a third cemented lens; the aperture stop 12 is positioned between the third and fourth lenses.
[0042] Aperture stop 12 is located at the front of the system, restricting large-angle light rays converged by the positive meniscus lens and cemented lens group in front of it. After passing through the aperture stop, light is confined to a smaller area, reducing interaction with other internal lens components and minimizing internal reflection and scattering. A set of cemented doublet lenses is placed at each end of aperture stop 12, using a symmetrical structure to achieve good achromatic effect, which is beneficial for improving infrared confocal sharpness. The system uses a total of three cemented lens groups, including two sets of cemented doublet lenses and one set of cemented triplet lenses, effectively reducing the overall system length while providing strong achromatic capability, thus improving the system's image sharpness.
[0043] In one possible implementation, the air gap between the first lens 1 and the first cemented lens is 0.1≤D1≤0.5, the air gap between the first cemented lens and the aperture stop 12 is 10≤D2≤15, the air gap between the aperture stop 12 and the second cemented lens is 0.5≤D3≤3, the air gap between the second cemented lens and the third cemented lens is 5≤D4≤9, the air gap between the third cemented lens and the ninth lens 9 is 0.1≤D5≤0.5, the air gap between the ninth lens 9 and the tenth lens 10 is 0.5≤D6≤3, and the air gap between the tenth lens 10 and the eleventh lens 11 is 10≤D7≤15.
[0044] In one possible implementation, the first lens 1 has a refractive index of 1.8 and an Abbe number of 37.2; the second lens 2 has a refractive index of 1.4 and an Abbe number of 90.2; the third lens 3 has a refractive index of 1.6 and an Abbe number of 37.3; the fourth lens 4 has a refractive index of 1.6 and an Abbe number of 42.6; the fifth lens 5 has a refractive index of 1.8 and an Abbe number of 35.1; the sixth lens 6 has a refractive index of 1.5 and an Abbe number of 60.1; the seventh lens 7 has a refractive index of 1.4 and an Abbe number of 90.2; the eighth lens 8 has a refractive index of 1.6 and an Abbe number of 34.7; the ninth lens 9 has a refractive index of 1.8 and an Abbe number of 62.6; the tenth lens 10 has a refractive index of 1.8 and an Abbe number of 42.7; and the eleventh lens 11 has a refractive index of 1.5 and an Abbe number of 68.9.
[0045] In one specific embodiment, the curvatures of the eleven optical spherical lenses satisfy the following relationship:
[0046] First lens 1: 30≤R1≤38 100≤R2≤107
[0047] Second lens 2: 22≤R1≤29 152≤R2≤158
[0048] Third lens 3: 152≤R1≤158 12≤R2≤18
[0049] Fourth lens 4: -32≤R1≤-26 15≤R2≤20
[0050] Fifth lens 5: 15≤R1≤20 -58≤R2≤-52
[0051] Lens 6: 107≤R1≤115 15≤R2≤20
[0052] Seventh Lens 7: 15≤R1≤20 -18≤R2≤-12
[0053] Lens 8: -18≤R1≤-12 -68≤R2≤-62
[0054] Ninth Lens 9: 39≤R1≤44 -44≤R2≤-38
[0055] Tenth lens 10: 32≤R1≤38R2=0
[0056] 11th Lens 11: -48≤R1≤-41 15≤R2≤20
[0057] Where R1 is the curvature of the object side surface and R2 is the curvature of the image side surface.
[0058] Preferably, the first lens 1 has positive optical power, the second lens 2 has positive optical power, the third lens 3 has negative optical power, the fourth lens 4 has negative optical power, the fifth lens 5 has positive optical power, the sixth lens 6 has positive optical power, the seventh lens 7 has negative optical power, the eighth lens 8 has negative optical power, the ninth lens 9 has positive optical power, the tenth lens 10 has positive optical power, and the eleventh lens 11 has negative optical power. The last lens is a negative optical power biconcave lens to diverge the light and achieve a large target surface. Two of the three sets of cemented lenses are made of ultra-low dispersion glass with an Abbe number of 94.5. This effectively reduces system chromatic aberration and improves infrared clarity. By using a combination of positive-positive-negative-negative-positive-negative-positive-positive-negative optical power, an optical system with a focal length of 50mm ± 5%, an image plane that meets the same image quality across the entire field of view, excellent infrared clarity, a resolution of 12MP, and an aperture of f / 1.5 can be achieved.
[0059] like Figure 2 The diagram shown is a standard dot matrix diagram of the optical system according to an embodiment of this utility model. The RMS radius is less than 2.57 (generally less than 3 is considered a preferred indicator), and the GEO radius is less than 10.5 (generally less than 20 is considered a preferred indicator).
[0060] Figure 3 This is a schematic diagram of the field curvature and distortion of the optical system in an embodiment of the present invention. The sagittal field curvature is 0.0329 mm, the meridional field curvature is 0.0216 mm, the maximum field of view is 10.006 degrees, and the maximum distortion is 0.4882%, which is excellent.
[0061] Figure 4 The modulation transfer function curve of this utility model embodiment shows that the MTF (modulation transfer function) is still greater than 0.35 at 200mm / lp.
[0062] Figures 5 to 10 The image shows the ray fan plots of an embodiment of this utility model, with results for image planes of 0mm, 3mm, 4.5mm, 6mm, 7.5mm, and 8.8mm. The 8.8mm dot plot shows that the target surface reaches 1'.
[0063] The first three lenses in this invention are meniscus lenses, which can converge light from a wider angle into the system, achieving a large aperture. A set of cemented doublet lenses is placed at each end of the aperture stop, using a symmetrical structure to achieve good achromatic effect and improve infrared confocal sharpness. The system consists of three cemented lens groups, including two sets of cemented doublet lenses and one set of cemented triplet lenses, effectively reducing the overall system length while maintaining strong achromatic capability and improving system imaging sharpness. The last lens is a negative power biconcave lens, which diverges light to achieve a large target surface. At a focal length of 50mm, it achieves the same image quality across the entire field of view for the target surface, with a resolution of up to 12MP. The MTF (modulation transfer function) remains greater than 0.35 at 200mm / lp, demonstrating outstanding overall performance.
[0064] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A fixed focus high definition infrared confocal large target imaging optical system characterized by: From the object plane to the image plane, the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, and an eleventh lens. Among these, the first, second, third, and sixth lenses are meniscus lenses, and the fourth and eleventh lenses are biconcave lenses. The fifth, seventh, and ninth lenses are biconvex lenses, and the tenth lens is a plano-convex lens. The second and third lenses are combined to form a first cemented lens, the fourth and fifth lenses are combined to form a second cemented lens, and the sixth, seventh, and eighth lenses are combined to form a third cemented lens. An aperture stop is positioned between the third and fourth lenses.
2. The fixed focus high definition infrared confocal large format imaging optical system of claim 1, wherein: The air gap between the first lens and the first cemented lens is 0.1≤D1≤0.5, the air gap between the first cemented lens and the aperture stop is 10≤D2≤15, the air gap between the aperture stop and the second cemented lens is 0.5≤D3≤3, the air gap between the second cemented lens and the third cemented lens is 5≤D4≤9, the air gap between the third cemented lens and the ninth lens is 0.1≤D5≤0.5, the air gap between the ninth lens and the tenth lens is 0.5≤D6≤3, and the air gap between the tenth lens and the eleventh lens is 10≤D7≤15.
3. The fixed focus high definition infrared confocal large format imaging optical system of claim 1, wherein: The curvatures of the eleven lenses satisfy the following relationship: First lens: 30≤R1≤38 100≤R2≤107 Second lens: 22≤R1≤29 152≤R2≤158 Third lens: 152≤R1≤158 12≤R2≤18 Fourth lens: -32≤R1≤-26 15≤R2≤20 Fifth lens: 15≤R1≤20 -58≤R2≤-52 Sixth lens: 107≤R1≤115 15≤R2≤20 Seventh lens: 15≤R1≤20 -18≤R2≤-12 Eighth lens: -18≤R1≤-12 -68≤R2≤-62 Ninth lens: 39≤R1≤44 -44≤R2≤-38 Tenth lens: 32≤R1≤38 R2=0 Eleventh lens: -48≤R1≤-41 15≤R2≤20.
4. The fixed focus high definition infrared confocal large format imaging optical system of claim 1, wherein: The first lens has a refractive index of 1.8 and an Abbe number of 37.2; the second lens has a refractive index of 1.4 and an Abbe number of 90.2; the third lens has a refractive index of 1.6 and an Abbe number of 37.3; the fourth lens has a refractive index of 1.6 and an Abbe number of 42.6; the fifth lens has a refractive index of 1.8 and an Abbe number of 35.1; the sixth lens has a refractive index of 1.5 and an Abbe number of 60.1; the seventh lens has a refractive index of 1.4 and an Abbe number of 90.2; the eighth lens has a refractive index of 1.6 and an Abbe number of 34.7; the ninth lens has a refractive index of 1.8 and an Abbe number of 62.6; the tenth lens has a refractive index of 1.8 and an Abbe number of 42.7; and the eleventh lens has a refractive index of 1.5 and an Abbe number of 68.
9.
5. The fixed focus high definition infrared confocal large format imaging optical system of claim 1, wherein: The first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, the fifth lens has positive optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, the tenth lens has positive optical power, and the eleventh lens has negative optical power.
6. The fixed focus high definition infrared confocal large format imaging optical system of claim 1, wherein: At least two of the first, second, and third cemented lenses are made of ultra-low dispersion glass.
7. The fixed focus high definition infrared confocal large format imaging optical system of claim 6, wherein: The Abbe number of the ultra-low dispersion glass is 94.5.