Surveying and mapping lens
By using a surveying lens with an eight-lens structure and employing three sets of cemented lens groups to correct chromatic aberration and astigmatism, the problem of optical distortion affecting measurement accuracy has been solved, thus realizing a high-precision and miniaturized surveying lens.
Patent Information
- Application Number
- CN202423307007.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-12-30
AI Technical Summary
The optical distortion of existing surveying lenses cannot meet the requirements of high-precision measurement, thus affecting the accuracy of the measurement.
It adopts an eight-lens structure, including three cemented lens groups. The first lens constricts light, and the third and fifth lenses suppress astigmatism, further correcting chromatic aberration and controlling optical distortion to within 0.2%.
It achieves high-precision measurement, with optical distortion controlled within 0.2%, and features a miniaturized and lightweight lens that supports 60-megapixel imaging.
Smart Images
Figure CN223624467U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical device technology, and in particular to a surveying lens. Background Technology
[0002] In surveying work, lens distortion can affect the accuracy of measurements, especially in applications requiring high-precision measurements. Surveying lenses are very sensitive to distortion, and currently, the optical distortion of surveying lenses cannot meet the requirements of these applications. Utility Model Content
[0003] In view of this, in order to solve one of the above problems, the purpose of this utility model embodiment is to provide a mapping lens that can further reduce optical distortion.
[0004] This utility model embodiment provides a mapping lens, which, from the object side to the image side, sequentially includes a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with positive optical power. The second lens and the third lens form a first cemented lens group, the fourth lens and the fifth lens form a second cemented lens group, and the sixth lens and the seventh lens form a third cemented lens group.
[0005] Optionally, the full field of view of the lens satisfies the following relationship:
[0006] 40°<2θ<50°
[0007] Where 2θ represents the full field of view of the lens.
[0008] Optionally, the total length of the lens and the image plane size of the lens satisfy the following relationship:
[0009] 2 <T / h<3.5
[0010] Where T represents the total length of the lens, and h represents the image plane size of the lens.
[0011] Optionally, the incident angle of the principal ray of the lens satisfies the following relationship:
[0012] 15 <CRA<20
[0013] CRA indicates the angle of incidence of the principal ray from the lens.
[0014] Optionally, the optical back focal length of the lens and the total length of the lens satisfy the following relationship:
[0015] 0.12 <BFL / T<0.3
[0016] Where BFL represents the optical back focal length of the lens, and T represents the total length of the lens.
[0017] Optionally, any one or more of the materials used in the first to the eighth lenses include spherical glass.
[0018] Optionally, the refractive index and Abbe number of the first lens satisfy the following relationship:
[0019] 1.4 <N1<1.6
[0020] 67 <V1<73
[0021] Where N1 represents the refractive index of the first lens and V1 represents the Abbe number of the first lens.
[0022] Optionally, the Abbe number of the third lens satisfies the following relationship:
[0023] 78 <V3<85
[0024] Where V3 represents the Abbe number of the third lens.
[0025] Optionally, the refractive index of the fifth lens satisfies the following relationship:
[0026] 1.8 <N5<2.1
[0027] N5 represents the refractive index of the fifth lens.
[0028] Optionally, the focal length of the lens satisfies the following relationship:
[0029] 50 <f<60
[0030] Where f represents the focal length of the lens.
[0031] The implementation of this utility model embodiment has the following beneficial effects: In this embodiment, the mapping lens includes eight lenses, including three cemented lens groups. The incident light is compressed and chromatic aberration is corrected by the first lens, the third and fifth lenses suppress astigmatism, and the first, second and third cemented lens groups further correct chromatic aberration, thereby further reducing optical distortion and controlling optical distortion to within 0.2%, achieving 60 million pixels. In addition, the lens is small and lightweight, optimizing the quality and size of the lens. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the structure of a surveying lens provided in an embodiment of this utility model;
[0033] Figure 2 This is an aberration diagram of a surveying lens provided in an embodiment of the present invention;
[0034] Figure 3 This is a field curvature diagram of a surveying lens provided in an embodiment of the present invention;
[0035] Figure 4 This is a peripheral illumination map of a surveying lens provided in an embodiment of the present invention;
[0036] Figure 5 This is a distortion map of a surveying lens provided in an embodiment of the present invention;
[0037] Figure 6 This is another aberration diagram of a surveying lens provided in this embodiment of the utility model;
[0038] Figure 7 This is another field curvature diagram of a surveying lens provided in this embodiment of the utility model;
[0039] Figure 8 This is another peripheral illumination map of a surveying lens provided in this embodiment of the utility model;
[0040] Figure 9 This is another distortion diagram of a surveying lens provided in this embodiment of the utility model. Detailed Implementation
[0041] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only for ease of explanation and do not limit the order of the steps. The execution order of each step in the embodiments can be adapted according to the understanding of those skilled in the art.
[0042] See Figure 1 This utility model embodiment provides a mapping lens, which, from the object side to the image side, sequentially includes a first lens L1 with positive optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with positive optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with negative optical power, a seventh lens L7 with positive optical power, and an eighth lens L8 with positive optical power. The second lens L2 and the third lens L3 form a first cemented lens group, the fourth lens L4 and the fifth lens L5 form a second cemented lens group, and the sixth lens L6 and the seventh lens L7 form a third cemented lens group.
[0043] See Figure 1The first lens L1 has a convex object-side surface S1 and a concave image-side surface S2. It is made of low-refractive-value, high-Abbe-number glass to reduce light intensity and correct chromatic aberration. The second lens L2 has a convex object-side surface S3 and a concave image-side surface S4 to reduce light intensity; it is made of crown glass. The third lens L3 has a convex object-side surface S5 and a concave image-side surface S6. The second and third lenses L2 are cemented together to suppress chromatic aberration. The fourth lens L4 has a concave object-side surface S6 and a concave image-side surface S7. The concave surface of the fifth lens helps adjust the angle of light incidence; the image-side surface S8 of the fifth lens is convex, and the fourth lens L4 is cemented with the fifth lens L5, which helps correct chromatic aberration; the object-side surface S9 of the sixth lens L6 is concave, and the image-side surface S10 is concave; the image-side surface S11 of the seventh lens L7 is convex, and the sixth lens L6 is cemented with the seventh lens L7; the object-side surface S12 of the eighth lens L8 is concave, and the image-side surface S13 is convex, which helps correct astigmatism and field curvature.
[0044] The first and second cemented lens groups effectively correct chromatic aberration. The selection of lens materials (glass), coating requirements, and the design of the internal black object mechanism all contribute to effective control over glare suppression.
[0045] Optionally, the full field of view of the lens satisfies the following relationship:
[0046] 40°<2θ<50°
[0047] Where 2θ represents the full field of view of the lens.
[0048] The field of view (FOV) is a crucial concept in optical engineering, determining the field of view of an optical instrument. The size of the FOV directly impacts the performance and application scenarios of optical equipment. A larger FOV results in a wider field of view, but the optical magnification will decrease accordingly. Simply put, when the size of the target object exceeds the FOV, part of the object will not be fully captured by the lens.
[0049] Optionally, the total length of the lens and the image plane size of the lens satisfy the following relationship:
[0050] 2 <T / h<3.5
[0051] Where T represents the total length of the lens, and h represents the image plane size of the lens.
[0052] The total length of a lens refers to the distance from the first surface of the lens to the image plane, reflecting the length of the internal optical components of the lens.
[0053] Optionally, the incident angle of the principal ray of the lens satisfies the following relationship:
[0054] 15 <CRA<20
[0055] CRA indicates the angle of incidence of the principal ray from the lens.
[0056] The angle of incidence of the principal ray is the angle between the incident ray and the normal to the lens surface when the ray enters the lens. In optics, the angle of incidence is the angle between the incident ray and the normal to the incident surface, and the angle of reflection is equal to the angle of incidence. When light enters the lens, it undergoes reflection and refraction at the lens surface. The smaller the angle of incidence, the more light energy is transmitted and the less light energy is reflected. Therefore, the smaller the angle of incidence of the principal ray, the higher the image sharpness. To reduce reflected light energy, an "anti-reflective coating" is usually applied to the lens surface, which increases transmitted light energy and improves image quality.
[0057] Optionally, the optical back focal length of the lens and the total length of the lens satisfy the following relationship:
[0058] 0.12 <BFL / T<0.3
[0059] Where BFL represents the optical back focal length of the lens, and T represents the total length of the lens.
[0060] Optical back focal length (BFL) is defined as the distance from the last surface of a lens in an optical system to the image plane. Several factors need to be considered when determining BFL, including the lens's focal length, aperture size, and lens design. A well-designed BFL ensures that light is correctly focused onto the image plane, thus improving image quality. Furthermore, adjusting the BFL can affect the overall length and weight of the system, which is particularly important for the design of portable devices.
[0061] Optionally, any one or more of the materials used in the first to the eighth lenses include spherical glass.
[0062] Spherical glass can focus more uniformly, reduce aberrations, and thus improve image quality. Compared with flat glass, spherical glass can better correct light refraction, reduce distortion and blurring, and make the image clearer and more realistic.
[0063] Optionally, the refractive index and Abbe number of the first lens satisfy the following relationship:
[0064] 1.4 <N1<1.6
[0065] 67 <V1<73
[0066] Where N1 represents the refractive index of the first lens and V1 represents the Abbe number of the first lens.
[0067] The low refractive index and high Abbe number of the first lens can further reduce light and correct chromatic aberration.
[0068] Optionally, the Abbe number of the third lens satisfies the following relationship:
[0069] 78 <V3<85
[0070] Where V3 represents the Abbe number of the third lens.
[0071] The third lens has a high Abbe number (low dispersion), which can effectively suppress astigmatism.
[0072] Optionally, the refractive index of the fifth lens satisfies the following relationship:
[0073] 1.8 <N5<2.1
[0074] N5 represents the refractive index of the fifth lens.
[0075] The fifth lens has a high refractive index, which can effectively suppress astigmatism.
[0076] Optionally, the focal length of the lens satisfies the following relationship:
[0077] 50 <f<60
[0078] Where f represents the focal length of the lens.
[0079] The focal length of the lens is determined based on the actual application, and this embodiment does not impose specific limitations. In one specific embodiment, the lens has a focal length of 56mm, an optical length of 65mm, a field of view of 42°, and an aperture of F5.6. The lens has a built-in aperture and shutter, which can be adjusted according to different ambient light conditions to achieve good imaging results.
[0080] focal length length Field of view aperture 56mm 65mm 42° F5.6
[0081] The mapping lens in this application is illustrated below with two specific embodiments.
[0082] Example 1
[0083] The structural parameters of the surveying lenses are shown in Table 1, and the focal length and capability values of each lens are shown in Table 2. Wherein, OBJ: object plane, STO: aperture, IMA: image plane, R: radius of curvature, D: distance from one surface to the next, N: lens refractive index, and V: lens Abbe number.
[0084] Table 1
[0085]
[0086]
[0087] Table 2
[0088]
[0089] The aberrations, field curvature, peripheral brightness ratio, and distortion of the surveying lens are as follows: Figures 2-5 Specifically, Figures 2-5 The wavelength of the medium curve is 435nm-656nm; Figure 2 Intermediate aberrations are controlled within the range of (-3μm to 2μm); Figure 3 The meridional field curvature and sagittal field curvature are controlled within the range of (-0.2mm to 0.2mm); because surveying requires strict distortion control, lens distortion is controlled within 0.5%. Figure 4 The peripheral light ratio of the lens is not less than 70% at an image height of 21.24mm; Figure 5 The Airy disk in the center field of view of the midpoint array diagram is controlled within 1.8 μm. Figures 2-5 The results show that the lens can accurately reproduce proportions, with minimal distortion and good color correction in surveying and mapping.
[0090] Example 2
[0091] The structural parameters of the surveying lenses are shown in Table 3, and the focal length and capability values of each lens are shown in Table 4. Wherein, OBJ: object plane, STO: aperture, IMA: image plane, R: radius of curvature, D: distance from one surface to the next, N: lens refractive index, and V: lens Abbe number.
[0092] Table 3
[0093]
[0094]
[0095] Table 4
[0096]
[0097] The aberrations, field curvature, peripheral brightness ratio, and distortion of the surveying lens are as follows: Figures 6-9 Specifically, Figures 6-9 The wavelength of the medium curve is 435nm-656nm; Figure 6 Intermediate aberrations are controlled within the range of (-3μm to 2μm); Figure 7 The meridional field curvature and sagittal field curvature are controlled within the range of (-0.2mm to 0.2mm); because surveying requires strict distortion control, lens distortion is controlled within 0.5%. Figure 8 The peripheral light ratio of the lens is not less than 70% at an image height of 21.5mm; Figure 9 The Airy disk in the center field of view of the midpoint array diagram is controlled within 1.8 μm. Figures 6-9 The results show that the lens can accurately reproduce proportions, with minimal distortion and good color correction in surveying and mapping.
[0098] The implementation of this utility model embodiment has the following beneficial effects: In this embodiment, the mapping lens includes eight lenses, including three cemented lens groups. The incident light is compressed and chromatic aberration is corrected by the first lens, the third and fifth lenses suppress astigmatism, and the first, second and third cemented lens groups further correct chromatic aberration, thereby further reducing optical distortion and controlling optical distortion to within 0.2%, achieving 60 million pixels. In addition, the lens is small and lightweight, optimizing the quality and size of the lens.
[0099] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.
Claims
1. A surveying lens, characterized in that, From the object side to the image side, the lens comprises, in sequence, a first lens with positive optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, and an eighth lens with positive optical power. The second lens and the third lens form a first cemented lens group, the fourth lens and the fifth lens form a second cemented lens group, and the sixth lens and the seventh lens form a third cemented lens group.
2. The mapping lens according to claim 1, characterized in that, The full field of view of the lens satisfies the following relationship: 40°<2θ<50° Where 2θ represents the full field of view of the lens.
3. The surveying lens according to claim 1, characterized in that, The total length of the lens and the image plane size of the lens satisfy the following relationship: 2 <T / h<3.5 Where T represents the total length of the lens, and h represents the image plane size of the lens.
4. The surveying lens according to claim 1, characterized in that, The incident angle of the principal ray of the lens satisfies the following relationship: 15 <CRA<20 CRA indicates the angle of incidence of the principal ray from the lens.
5. The mapping lens according to claim 1, characterized in that, The optical back focal length of the lens and the total length of the lens satisfy the following relationship: 0.12 <BFL / T<0.3 Where BFL represents the optical back focal length of the lens, and T represents the total length of the lens.
6. The mapping lens according to claim 1, characterized in that, The material of any one or more of the first to eighth lenses includes spherical glass.
7. The surveying lens according to claim 1, characterized in that, The refractive index and Abbe number of the first lens satisfy the following relationship: 1.4<N1<1.6 67<V1<73 Where N1 represents the refractive index of the first lens and V1 represents the Abbe number of the first lens.
8. The mapping lens according to claim 1, characterized in that, The Abbe number of the third lens satisfies the following relationship: 78<V3<85 Where V3 represents the Abbe number of the third lens.
9. The surveying lens according to claim 1, characterized in that, The refractive index of the fifth lens satisfies the following relationship: 1.8<N5<2.1 N5 represents the refractive index of the fifth lens.
10. The surveying lens according to claim 1, characterized in that, The focal length of the lens satisfies the following relationship: 50<f<60 Where f represents the focal length of the lens.