Low-distortion mapping lens
By designing a low-distortion mapping lens composed of nine lenses and using specific lens materials and structures, the problem of optical distortion affecting measurement accuracy was solved, and the miniaturization and weight reduction of the lens for high-precision mapping were achieved.
Patent Information
- Application Number
- CN202423307295.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-11-28
- 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.
A low-distortion mapping lens is designed, consisting of nine lenses, including two sets of cemented lens groups. Through specific lens materials and structural design, optical distortion is controlled to within 0.2%, optimizing lens quality and size.
It effectively reduces optical distortion, improves measurement accuracy, and features a small and lightweight lens to meet the needs of high-precision surveying.
Smart Images
Figure CN223611781U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to optical device technical field especially relates to a low distortion mapping camera lens. BACKGROUND
[0002] In the mapping work, the lens distortion can influence the accuracy of measurement, especially in the application needing high precision measurement, the mapping camera lens is very strict to distortion, and the optical distortion of the current mapping camera lens still cannot satisfy the application. CONTENT
[0003] Therefore, in order to solve one of the above problems, the embodiment of the utility model aims at providing a low distortion mapping camera lens, which can further reduce optical distortion.
[0004] The embodiment of the utility model provides a low distortion mapping camera lens, which comprises a first lens with specific negative optical power, a second lens and a third lens with positive optical power, a fourth lens, a fifth lens and a sixth lens with negative optical power, a seventh lens and an eighth lens with positive optical power, and a ninth lens with negative optical power from the object side to the image side.
[0005] Optionally, the full field angle of the lens satisfies the following relationship:
[0006] 45° < 2θ < 65°
[0007] Wherein, 2θ represents the full field angle of the lens.
[0008] Optionally, the total length of the lens and the image size of the lens satisfy the following relationship:
[0009] 2 < T / h < 3.5
[0010] Wherein, T represents the total length of the lens, and h represents the image size of the lens.
[0011] Optionally, the chief ray angle of incidence of the lens satisfies the following relationship:
[0012] 20 < CRA < 26
[0013] Wherein, CRA represents the chief ray angle of incidence of 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] Wherein, BFL represents the optical back focal length of the lens, and T represents the total length of the lens.
[0017] Optionally, a material of any one or more of the first lens to the ninth lens comprises spherical glass.
[0018] Optionally, a refractive index and an Abbe number of the first lens satisfy the following relationship:
[0019] 1.45 < N1 < 1.6
[0020] 63 < V1 < 65
[0021] wherein N1 represents the refractive index of the first lens, and V1 represents the Abbe number of the first lens.
[0022] Optionally, a refractive index of the third lens satisfies the following relationship:
[0023] 1.8 < N3 < 2.1
[0024] wherein N3 represents the refractive index of the third lens.
[0025] Optionally, a refractive index of the eighth lens satisfies the following relationship:
[0026] 1.85 < N8 < 2.05
[0027] wherein N8 represents the refractive index of the eighth lens.
[0028] Optionally, a focal length of the lens satisfies the following relationship:
[0029] 35 < f < 45
[0030] wherein f represents the focal length of the lens.
[0031] The embodiment of the present application has the following beneficial effects: the low-distortion surveying and mapping lens in the embodiment comprises nine lenses, two groups of cemented lens groups, incident light is shrunk and chromatic aberration is corrected by the first lens, aberration is controlled by the third lens, chromatic aberration is further corrected by the first cemented lens group and the second cemented lens group, and aberration is further controlled by the eighth lens, so that optical distortion is further reduced and is controlled within 0.2%, and in addition, the lens is small and light, and the mass and size of the lens are optimized. BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 is a structure schematic diagram of a low-distortion surveying and mapping lens provided by the embodiment of the present application;
[0033] Figure 2 is an aberration diagram of a low-distortion surveying and mapping lens provided by the embodiment of the present application;
[0034] Figure 3The utility model embodiment provides a low distortion surveying and mapping lens's field curve drawing.
[0035] Figure 4 The utility model embodiment provides a low distortion surveying and mapping lens's periphery bright drawing.
[0036] Figure 5 The utility model embodiment provides a low distortion surveying and mapping lens's distortion drawing.
[0037] Figure 6 The utility model embodiment provides another low distortion surveying and mapping lens's aberration drawing.
[0038] Figure 7 The utility model embodiment provides another low distortion surveying and mapping lens's field curve drawing.
[0039] Figure 8 The utility model embodiment provides another low distortion surveying and mapping lens's periphery bright drawing.
[0040] Figure 9 The utility model embodiment provides another low distortion surveying and mapping lens's distortion drawing. Specific implementation
[0041] The utility model will be further explained in detail below in combination with the drawings and specific embodiment. For the step numbering in the following embodiment, it is only set up for facilitating the explanation and illustration, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of the person skilled in the art.
[0042] As Figure 1 The utility model embodiment provides a low distortion surveying and mapping lens, from object side to image side includes the first lens L1 with specific negative focal length, the second lens L2 and third lens L3 with positive focal length, the fourth lens L4, fifth lens L5 and sixth lens L6 with negative focal length, the seventh lens L7 and eighth lens L8 with positive focal length, the ninth lens L9 with negative focal length, the fourth lens L4 and the fifth lens L5 form the first cemented lens group, and the sixth lens L6 and the seventh lens L7 form the second cemented lens group.
[0043] Specifically, refer to Figure 1The object side S1 of the first lens L1 is a convex surface, the image side S2 is a concave surface, the material is selected as low refractive index and high Abbe number glass, and the light rays are contracted to correct chromatic aberration; the object side S3 of the second lens L2 is a convex surface, the image side S4 is a concave surface, and the material is selected as crown glass; the object side S5 of the third lens L3 is a convex surface, and the image side S6 is a concave surface; the object side S7 of the fourth lens L4 is a plane, and the image side S8 is a concave surface; the object side S9 of the fifth lens L5 is a convex surface, the fourth lens L4 and the fifth lens L5 are glued together, which is beneficial to correcting chromatic aberration; the object side S10 of the sixth lens L6 is a concave surface, and the image side S11 is a convex surface; the object side S12 of the seventh lens L7 is a convex surface, the sixth lens L6 and the seventh lens L7 are glued together; the object side S13 of the eighth lens L8 is a convex surface, and the image side S14 is a convex surface; and the object side S15 of the ninth lens L9 is a concave surface, and the image side S14 is a convex surface. The first glued lens group and the second glued lens group effectively correct chromatic aberration.
[0044] The material of the lens is selected as glass, the requirements of film plating, and the design of the internal black object mechanism of the lens are all effective controls for suppressing glare.
[0045] Optionally, the full field angle of the lens satisfies the following relationship:
[0046] 45° < 2θ < 65°
[0047] Wherein, 2θ represents the full field angle of the lens.
[0048] The full field angle (FOV) is an important concept in optical engineering, which determines the field of view of optical instruments. The size of the field angle directly affects the performance and application scenarios of optical equipment. The larger the field angle, the wider the field of view, but the optical magnification will decrease accordingly. In simple terms, when the size of the target object exceeds the field angle, part of the object will not be completely included in the lens.
[0049] Optionally, the total length of the lens and the image size of the lens satisfy the following relationship:
[0050] 2 < T / h < 3.5
[0051] Wherein, T represents the total length of the lens, and h represents the image size of the lens.
[0052] The total length of the lens refers to the distance from the first surface of the lens to the image surface, which reflects the length of the internal optical components of the lens.
[0053] Optionally, the chief ray incidence angle of the lens satisfies the following relationship:
[0054] 20 < CRA < 26
[0055] Wherein, CRA represents the chief ray incidence angle of the lens.
[0056] The chief ray incidence angle refers to the angle between the light entering the lens and the normal of the lens surface. In optics, the incidence angle is the angle between the incident light and the normal of the incident surface, while the reflection angle is equal to the incidence angle. When light enters the lens, it will produce reflection and refraction on the lens surface. The smaller the incidence angle, the more transmitted light energy and the less reflected light energy. Therefore, the smaller the chief ray incidence angle of the lens, the higher the clarity of the image. In order to reduce the reflected light energy, a layer of "anti-reflection film" is usually coated on the surface of the lens, which can increase the transmitted light energy and improve the imaging 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] Wherein, BFL represents the optical back focal length of the lens, and T represents the total length of the lens.
[0060] The optical back focal length (BFL) is defined as the distance from the last surface of the lens in the optical system to the image plane. BFL needs to consider multiple factors, including the focal length of the lens, the aperture size, the design of the lens, etc. Reasonable design of BFL can ensure that light can be correctly focused on the imaging plane, thereby improving the imaging quality. In addition, the adjustment of BFL can also affect the overall length and weight of the system, which is particularly important for the design of portable devices.
[0061] Optionally, the material of any one or more of the first lens to the ninth lens includes spherical glass.
[0062] Spherical glass can focus more uniformly, reduce aberration, and thus improve imaging quality; compared with flat glass, spherical glass can better correct light refraction, reduce distortion and blurring, making the image clearer and more realistic.
[0063] Optionally, the refractive index and Abbe number of the first lens satisfy the following relationship:
[0064] 1.45 < N1 < 1.6
[0065] 63 < V1 < 65
[0066] Wherein, 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 shrink the light and correct chromatic aberration.
[0068] Optionally, the refractive index of the third lens satisfies the following relationship:
[0069] 1.8 < N3 < 2.1
[0070] N3 represents the refractive index of the third lens.
[0071] The third lens adopts a high refractive index material, which can further effectively control aberration.
[0072] Optionally, the refractive index of the eighth lens satisfies the following relationship:
[0073] 1.85 < N8 < 2.05
[0074] N8 represents the refractive index of the eighth lens.
[0075] The eighth lens adopts a high refractive index material, which can further effectively control aberration.
[0076] Optionally, the focal length of the lens satisfies the following relationship:
[0077] 35 < f < 45
[0078] f represents the focal length of the lens.
[0079] focal length length angle of view aperture 40mm 65mm 57° F5.6
[0080] The focal length of the lens is determined according to actual application, which is not specifically limited in the embodiment. In a specific embodiment, the focal length of the lens is 40 mm, the optical length is 65 mm, the field of view is 57°, and the aperture is F5.6. The lens is built-in aperture shutter, which can adjust the aperture shutter according to different environment light to achieve good imaging effect. In the embodiment, the pixel can reach 60 million.
[0081] Two specific embodiments of the low-distortion mapping lens in the application are described below.
[0082] Embodiment one
[0083] The structural parameters of the low-distortion mapping lens are shown in Table One, and the focal length and capacity value of each lens are shown in Table Two. Among them, OBJ: object plane, STO: aperture, IMA: image plane, R: radius of curvature, D: distance from the surface to the next surface, N: refractive index of the lens, V: Abbe number of the lens.
[0084] Table One
[0085]
[0086]
[0087] Table Two
[0088]
[0089] Aberration, field curvature, peripheral light ratio and distortion of the low-distortion surveying lens are as follows. Figures 2-5 Specifically, Figures 2-5 the middle curve wavelength is 435nm-650nm, Figure 2 the middle aberration is controlled within the range of (-2μm-4μm), Figure 3 the meridional field curvature value and sagittal field curvature value are controlled within the range of (-0.2mm-0.2mm); because the surveying lens has strict requirements on distortion, the lens distortion is controlled within 0.2%, Figure 4 the lens peripheral light ratio at the image height of 21.5mm is not less than 40%, Figure 5 the center field Airy disk of the midpoint column diagram is controlled within 1.5μm. Figures 2-5 The results show that the lens can restore the real proportion in surveying and shooting, has small distortion and good chromatic aberration correction.
[0090] Example Two
[0091] The structural parameters of the low-distortion surveying lens are shown in Table Three, and the focal length and capacity values of each lens are shown in Table Four. Among them, OBJ: object plane, STO: aperture, IMA: image plane, R: radius of curvature, D: distance from the surface to the next surface, N: refractive index of the lens, and V: Abbe number of the lens.
[0092] Table Three
[0093]
[0094]
[0095] Table Four
[0096]
[0097]
[0098] Aberration, field curvature, peripheral light ratio and distortion of the low-distortion surveying lens are as follows. Figures 6-9 Specifically, Figures 6-9 the middle curve wavelength is 435nm-650nm, Figure 6 the middle aberration is controlled within the range of (-2μm-4μm), Figure 7 the meridional field curvature value and sagittal field curvature value are controlled within the range of (-0.2mm-0.2mm); because the surveying lens has strict requirements on distortion, the lens distortion is controlled within 0.2%, Figure 8 the lens peripheral light ratio at the image height of 21.5mm is not less than 40%, Figure 9 the center field Airy disk of the midpoint column diagram is controlled within 1.5μm. Figures 6-9 The results show that the lens can restore the real proportion in surveying and shooting, has small distortion and good chromatic aberration correction.
[0099] The embodiment of the present application has the following advantages: the low-distortion surveying and mapping lens in the embodiment comprises nine lenses, wherein two groups of cemented lens groups are arranged, incident light passes through the first lens to be contracted and chromatic aberration is corrected, the third lens controls aberration, the first cemented lens group and the second cemented lens group further correct chromatic aberration, and the eighth lens further controls aberration, so that optical distortion is further reduced and is controlled within 0.2%, and in addition, the lens is small in size and light in weight, and the mass and size of the lens are optimized.
[0100] The above is a specific description of the preferred embodiment of the present application, but the present application is not limited to the above-mentioned embodiment, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.
Claims
1. A low-distortion mapping lens characterized by, From the object side to the image side, the lens sequentially comprises a first lens with a specific negative refractive power, a second lens and a third lens with positive refractive power, a fourth lens, a fifth lens and a sixth lens with negative refractive power, a seventh lens and an eighth lens with positive refractive power, and a ninth lens with negative refractive power; the fourth lens and the fifth lens form a first cemented lens group, and the sixth lens and the seventh lens form a second cemented lens group.
2. The low-distortion mapping lens of claim 1, wherein, The full field angle of the lens satisfies the following relationship: 45° < 2θ < 65°, wherein 2θ represents the full field angle of the lens. The total length of the lens and the image size of the lens satisfy the following relationship:
3. The low-distortion mapping lens of claim 1, wherein, 2 < T / h < 3.5, wherein T represents the total length of the lens, and h represents the image size of the lens. The chief ray incidence angle of the lens satisfies the following relationship: 20 < CRA < 26, wherein CRA represents the chief ray incidence angle of the lens.
4. The low-distortion mapping lens of claim 1, wherein, 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, wherein BFL represents the optical back focal length of the lens, and T represents the total length of the lens. The material of any one or more of the first lens to the ninth lens comprises spherical glass.
5. The low-distortion mapping lens of claim 1, wherein, The refractive index and the Abbe number of the first lens satisfy the following relationship: N1 < 1.7, V1 > 30, wherein N1 represents the refractive index of the first lens, and V1 represents the Abbe number of the first lens. The refractive index of the third lens satisfies the following relationship:
6. The low-distortion mapping lens of claim 1, wherein, N3 < 1.7, wherein N3 represents the refractive index of the third lens.
7. The low-distortion mapping lens of claim 1, wherein, The refractive index of the eighth lens satisfies the following relationship: 1.45<N1<1.6 63<V1<65 N8 < 1.7, wherein N8 represents the refractive index of the eighth lens.
8. The low-distortion mapping lens of claim 1, wherein, The focal length of the lens satisfies the following relationship: 1.8<N3<2.1 f > 2.5, wherein f represents the focal length of the lens.
9. The low-distortion mapping lens of claim 1, wherein, 1.85<N8<2.05 10. The low-distortion mapping lens of claim 1, wherein, 35<f<45