Optical lens
By designing five glass lenses and adjusting the combination of lens shape and optical power, the problems of high cost and poor environmental adaptability of existing optical lenses are solved, achieving high-pixel, miniaturized, high-definition, and large-aperture imaging effects, suitable for imaging needs in harsh environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN JIUZHOU OPTICAL CO LTD
- Filing Date
- 2025-05-08
- Publication Date
- 2026-04-21
AI Technical Summary
While existing automotive optical lenses achieve high resolution, wide field of view, and miniaturization, they are also expensive and struggle to maintain clear imaging in harsh environments.
The imaging system employs a five-glass lens structure. By adjusting the lens shape, material, and optical power combination, the imaging system is designed, including a combination of negative optical power, positive optical power, and cemented lenses. The total optical length and aperture number are controlled to ensure clear imaging within a temperature range of -40℃ to +85℃.
It achieves high pixel count, miniaturization, high definition, large aperture, and weak ghosting, while reducing costs. It is suitable for imaging needs in harsh environments and meets the requirements of imaging chips with more than 5 million pixels.
Smart Images
Figure CN224152738U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of optical device technology, and in particular to an optical lens. Background Technology
[0002] With the development of autonomous driving technology, ADAS (Advanced Driver Assistance Systems) has become standard equipment in many cars. As a key component of these systems, automotive cameras have also experienced rapid development. These cameras are crucial for acquiring external information, placing higher demands on the performance and structure of forward-facing optical lenses. For example, they require high resolution, a wide field of view, miniaturization, a large aperture, high relative illumination, and high resolution to meet the needs of automotive applications.
[0003] To improve image quality, methods such as adding lenses or using more aspherical glass lenses are generally employed. However, adding lenses or using aspherical glass lenses significantly increases production costs. With the increasing demands for automotive automation, the need for a greater number of automotive lenses is also growing. Reducing the cost of automotive lenses and improving image quality have become urgent needs for the automotive industry. Utility Model Content
[0004] This invention provides an optical lens that achieves high resolution, miniaturization, high definition, large aperture, weak ghosting, and a total length of less than 24mm, greatly reducing costs.
[0005] This application provides an optical lens, including a first lens, a second lens, an aperture stop, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object plane to the image plane;
[0006] Along the optical axis from the object plane to the image plane,
[0007] The first lens has negative optical power, and its object side is convex while its image side is concave.
[0008] The second lens has positive optical power, and its object side is convex, as is its image side;
[0009] The third lens has positive optical power, and its object side is convex, as is its image side;
[0010] The fourth lens has positive optical power, and its object side is convex, as is its image side;
[0011] The fifth lens has negative optical power, and its image-side surface is concave while its image-side surface is flat.
[0012] Optionally, the total optical length TTL of the optical lens and the image height H corresponding to the maximum field of view of the optical lens satisfy the following relationship:
[0013] 8 < TTL / H < 8.5.
[0014] Optionally, the total focal length F of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: TTL / F < 5.5.
[0015] Optionally, the optical back focal length (BFL) of the optical lens and the total optical length (TTL) of the optical lens satisfy the following condition: BFL / TTL > 0.5.
[0016] Optionally, the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: ENPD / TTL > 0.1.
[0017] Optionally, the focal length values f1 of the first lens, f2 of the second lens, f3 of the third lens, f4 of the fourth lens, and f5 of the fifth lens satisfy the following relationship with the total focal length value F of the optical lens:
[0018] -2 <f1 / F<0;0<f2 / F<2;1.8<f3 / F<3;0<f4 / F<2;-3<f5 / F<0。
[0019] Optionally, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy the following condition: 0.5 < |f4 / f5| < 1.5; the fourth lens and the fifth lens form a cemented lens;
[0020] The focal length f45 of the cemented lens and the total focal length F of the optical lens satisfy the following condition: 7 ≤ |f45 / F| ≤ 10.
[0021] Optionally, the refractive index Nd1 of the first lens satisfies: Nd1≥1.75;
[0022] The Abbe number Vd4 and refractive index Nd4 of the fourth lens and the Abbe number Vd5 and refractive index Nd5 of the fifth lens satisfy the following conditions: 3 < Vd4 / Vd5 < 3.5; 0.8 < Nd4 / Nd5 < 0.9.
[0023] Optionally, the central radius of curvature R1 of the object side of the first lens, the central radius of curvature R2 of the image side of the first lens, and the central thickness d1 of the first lens satisfy the following: 0.8≤R1 / (R2+d1)≤1.2.
[0024] Optionally, the central radius of curvature R1 of the first lens object side and the total focal length F of the optical lens satisfy the following condition: 0.5 < R1 / F < 1.5; the central radius of curvature R5 of the third lens object side and the total focal length F of the optical lens satisfy the following condition: R5 / F > 1.6.
[0025] The optical lens provided in this application adopts a 5-element structure. By adjusting the lens shape, lens material combination and different optical power combinations, it achieves the technical effects of high pixel count, miniaturization, high definition, large aperture, weak ghosting and a total length of less than 24mm, which greatly reduces the cost.
[0026] Compared with the prior art, the optical lens provided in this application has at least the following advantages:
[0027] (1) The lens uses five glass lenses and can clearly image within a temperature range of -40℃ to +85℃. It is particularly suitable for video fields such as action cameras and car cameras that are subject to harsh environments.
[0028] (2) The aperture of this lens is F1.55 or less, which can meet the imaging needs of darker environments.
[0029] (3) The lens produces clear images by reasonably configuring the optical power combination between the lenses, and can be matched with imaging chips with more than 5 million pixels. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the structure of an optical lens provided in Embodiment 1 of this application;
[0031] Figure 2 A ray fan pattern of an optical lens provided in Embodiment 1 of this application;
[0032] Figure 3 An axial aberration curve of an optical lens provided in Embodiment 1 of this application;
[0033] Figure 4 A field curvature distortion diagram of an optical lens provided in Embodiment 1 of this application;
[0034] Figure 5 This is a schematic diagram of the structure of an optical lens provided in Embodiment 2 of this application;
[0035] Figure 6 This is a ray fan pattern of an optical lens provided in Embodiment 2 of this application;
[0036] Figure 7 This is an axial aberration curve of an optical lens provided in Embodiment 2 of this application;
[0037] Figure 8This is a field curvature distortion diagram of an optical lens provided in Embodiment 2 of this application;
[0038] Figure 9 This is a schematic diagram of the structure of an optical lens provided in Embodiment 3 of this application;
[0039] Figure 10 This application provides a ray fan pattern for an optical lens according to Embodiment 3.
[0040] Figure 11 An axial aberration curve of an optical lens provided in Embodiment 3 of this application;
[0041] Figure 12 This is a field curvature distortion diagram of an optical lens provided in Embodiment 3 of this application. Detailed Implementation
[0042] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.
[0043] Figure 1 This is a schematic diagram of the structure of an optical lens provided in Embodiment 1 of this application. Figure 1 As shown, the optical lens 100 provided in this embodiment includes a first lens 11, a second lens 12, an aperture stop STO, a third lens 13, a fourth lens 14, and a fifth lens 15 arranged sequentially along the optical axis from the object plane to the image plane. Along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is the object-side surface, and the surface of the lens near the image plane is the image-side surface. The first lens 11 has negative optical power, its object-side surface is convex, and its image-side surface is concave. The second lens 12 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The third lens 13 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fourth lens 14 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fifth lens 15 has negative optical power, its image-side surface is concave, and its image-side surface is flat.
[0044] Optical power is equal to the difference between the convergence of light beams at the image plane and the convergence of light beams at the image plane. It characterizes the ability of an optical system to deflect light rays. The larger the absolute value of optical power, the stronger the ability to bend light rays; the smaller the absolute value of optical power, the weaker the ability to bend light rays. When optical power is positive, the refraction of light rays is converging; when optical power is negative, the refraction of light rays is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).
[0045] For example, refer to Figure 1 As shown, along the optical axis from the object plane M1 to the image plane M2, the optical power combination of the five lenses in this application is as follows: the first lens 11 has negative optical power, the second lens 12 has positive optical power, the third lens 13 has positive optical power, the fourth lens 14 has positive optical power, and the fifth lens 15 has negative optical power.
[0046] Reference Figure 1 As shown, the surface of the lens closest to the object plane M1 is the object-side surface, and the surface of the lens closest to the image plane M2 is the image-side surface. The surface shape of the first lens 11 is convex-concave; the surface shape of the second lens 12 is convex-convex; the surface shape of the third lens 13 is convex-convex; the surface shape of the fourth lens 14 is convex-convex; and the surface shape of the fifth lens 15 is concave-flat. By combining the surface shapes of the above lenses, the optical power can be reasonably allocated, space can be effectively saved, and the application scenarios of the lens can be expanded.
[0047] The first lens 11 is a convex-concave negative power lens, which ensures that light has a larger aperture before entering the aperture stop STO, thereby increasing the lens aperture. By placing the aperture stop STO near the image side of the second lens, the generation of optical astigmatism can be reduced, and it is beneficial to gather the light entering the optical system, reduce the rear aperture of the optical lens, and improve the lens image quality.
[0048] Meanwhile, the third lens 13 is a convex-convex type and the fourth lens 14 is a convex-convex type. The fourth lens 14 and the fifth lens 15 form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens.
[0049] In addition, the image side of the fifth lens 15 is flat, which can reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.
[0050] Based on the above embodiments, refer to Figure 1 The total optical length (TTL) of the optical lens and the image height (H) corresponding to the maximum field of view of the optical lens must satisfy the following relationship: 8 < TTL / H < 8.5. By using this range, a large image area can be achieved while better compressing the overall length of the lens, enabling miniaturization of the lens design and facilitating its mounting on other imaging devices.
[0051] Based on the above embodiments, refer to Figure 1 The focal length F of the entire optical lens and the total optical length TTL of the optical lens must satisfy the following condition: TTL / F < 5.5. Adopting this range helps to control the overall length of the lens and obtain a miniaturized optical lens.
[0052] Based on the above embodiments, referring to Figure 1 , the optical back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: BFL / TTL > 0.5. Adopting the above range is beneficial to realizing the miniaturization of the optical lens, and at the same time restricting the back focal length of the optical lens, which is beneficial to the assembly of the module.
[0053] Based on the above embodiments, referring to Figure 1 , the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy: ENPD / TTL > 0.1. Adopting the above range is beneficial to realizing a small FNO (f-number), and meeting the above range is beneficial to realizing the large aperture characteristic, providing more incident light for the optical lens.
[0054] Among them, the refractive index is the ratio of the speed of light in vacuum to the speed of light in the medium, mainly used to describe the refractive ability of the material to light, and the refractive indices of different materials are different. The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more serious the medium dispersion, the smaller the Abbe number; conversely, the lighter the medium dispersion, the larger the Abbe number.
[0055] Based on the above embodiments, referring to Figure 1 , the refractive index Nd1 of the first lens 11 satisfies: Nd1 ≥ 1.75. Among them, the first lens 11 can select a high refractive index material. Adopting the above range is beneficial to compressing the incident light, reducing the front aperture diameter of the optical lens, and at the same time improving the imaging quality.
[0056] Based on the above embodiments, referring to Figure 1 , the focal length value f1 of the first lens 11 and the overall focal length value F of the optical lens satisfy: -2 < f1 / F < 0. Meeting the above range, the first lens 11 can have an appropriate negative optical power, which is beneficial to expanding the field angle of the optical lens.
[0057] Based on the above embodiments, referring to Figure 1 , the focal length value f2 of the second lens 12 and the overall focal length value F of the optical lens satisfy: 0 < f2 / F < 2. Meeting the above range, the second lens 12 can have an appropriate positive optical power, which is beneficial to the smooth transition of light to the third lens 13, facilitating the correction of astigmatism and field curvature, and improving the imaging quality of the optical lens.
[0058] Based on the above embodiments, referring to Figure 1 , the focal length value f3 of the third lens 13 and the overall focal length value F of the optical lens satisfy: 1.8 < f3 / F < 3. Meeting the above range, by reasonably controlling the focal length of the third lens 13, the optical power of the entire optical system can be reasonably distributed, which is beneficial to realizing the temperature stability characteristic of the optical lens and ensuring good imaging quality of the lens under high and low temperature conditions.
[0059] Based on the above embodiments, referring to Figure 1 , the focal length value f4 of the fourth lens 14 and the overall focal length value F of the optical lens satisfy: 0 < f4 / F < 2. Meeting the above range, the fourth lens 14 can have an appropriate positive optical power, which is beneficial to the smooth transition of light to the fifth lens 15, facilitating the correction of astigmatism and field curvature, and improving the imaging quality of the optical lens.
[0060] Based on the above embodiments, referring to Figure 1 , the focal length value f5 of the fifth lens 15 and the overall focal length value F of the optical lens satisfy: -3 < f5 / F < 0. Meeting the above range, the fifth lens 15 can have an appropriate negative optical power, which is beneficial to increasing the imaging area of the optical lens and at the same time balancing various aberrations generated by the fifth lens 15, improving the imaging quality of the optical lens.
[0061] Based on the above embodiments, referring to Figure 1 , the fourth lens 14 and the fifth lens 15 are cemented, and the focal length value f4 of the fourth lens 14 and the focal length value f5 of the fifth lens 15 satisfy: 0.5 < |f4 / f5| < 1.5. Meeting the above range, the cementing of two positive and negative optical power lenses, the fourth positive lens 14 and the fifth negative lens 15, can achieve the effect of eliminating chromatic aberration.
[0062] Based on the above embodiments, referring to Figure 1 , the focal length value f45 of the cemented lens and the overall focal length value F of the optical lens satisfy: 7 ≤ |f45 / F| ≤ 10. Meeting the above range, by reasonably setting the optical power of the cemented lens, the chromatic aberration correction ability of the fourth lens 14 and the fifth lens 15 can be effectively improved, making the light passing through the cemented lens enter the image plane more evenly, thereby improving the imaging quality of the optical lens.
[0063] Based on the above embodiments, referring to Figure 1 , the Abbe number Vd4 and refractive index Nd4 of the fourth lens 14 and the Abbe number Vd5 and refractive index Nd5 of the fifth lens 15 satisfy: 3 < Vd4 / Vd5 < 3.5; 0.8 < Nd4 / Nd5 < 0.9. Meeting the above range, by increasing the difference in Abbe numbers and refractive indices between the fourth lens 14 and the fifth lens 15, it is more beneficial to eliminate chromatic aberration.
[0064] Based on the above embodiments, referring to Figure 1The central radius of curvature R1 of the object side of the first lens 11, the central radius of curvature R2 of the image side of the first lens 11, and the central thickness d1 of the first lens 11 satisfy the following condition: 0.8 ≤ R1 / (R2+d1) ≤ 1.2. Satisfying the above range can effectively balance the spherical aberration and coma generated by the first lens 11 itself, thereby improving the imaging quality of the optical lens.
[0065] Based on the above embodiments, refer to Figure 1 The central radius of curvature R1 of the object side of the first lens 11 and the total focal length F of the optical lens satisfy the following condition: 0.5 < R1 / F < 1.5. Satisfying this range helps to control the lower limit of the focal length of the first lens 11 and increases the field of view of the optical lens, thereby meeting the needs of wide-range shooting; at the same time, controlling the upper limit of the focal length of the first lens 11 helps to reduce the effective aperture of the lens and achieve miniaturization.
[0066] Based on the above embodiments, refer to Figure 1 The central radius of curvature R5 of the object-side surface of the third lens 13 and the overall focal length F of the optical lens satisfy the condition: R5 / F > 1.6. Meeting this range allows for the alteration of the relative position of the pupil image of the ghost image reflected from the object-side surface of the third lens 13 on the focal plane. By controlling the radius of curvature of the third lens 13, the pupil image of the ghost image can be moved away from the focal plane, effectively reducing the relative energy value of the ghost image, achieving the requirement of weak ghosting, and thus improving image quality.
[0067] Reference Figure 1 As shown in the embodiments of this application, each lens of the optical lens can be fixed in a lens barrel and sealed or vacuum-sealed. The user fixes each lens to ensure the stability and clarity of each lens surface and to ensure image quality. Each lens will not be shown in detail in the embodiments of this application.
[0068] Optional, refer to Figure 1 As shown, the optical lens 100 may further include a flat glass CG disposed in the optical path between the fifth lens 15 and the image plane M2. The flat glass CG can protect the photosensitive chip in the imaging sensor. The imaging chip is used to convert the light signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.
[0069] The optical lens provided in this application has at least the following advantages compared to the prior art:
[0070] (1) The lens uses five glass lenses and can clearly image within a temperature range of -40℃ to +85℃. It is particularly suitable for video fields such as action cameras and car cameras that are subject to harsh environments.
[0071] (2) The aperture of this lens is F1.55 or less, which can meet the imaging needs of darker environments.
[0072] (3) The lens produces clear images by reasonably configuring the optical power combination between the lenses, and can be matched with imaging chips with more than 5 million pixels.
[0073] The following are some specific embodiments to illustrate the optical performance parameters of the optical lens provided in this application.
[0074] As one possible implementation method, please refer to [reference]. Figure 1 Table 1 shows the optical physical parameters of the first lens 11 to the fifth lens 15 in an optical lens 100 provided in Embodiment 1 of this application. The units for the radius of curvature R and thickness d are millimeters (mm). Table 2 shows the aspherical coefficient values of the aspherical lenses in the optical lens 100 provided in Embodiment 1 of this application.
[0075] Table 1 Design values of optical physical parameters of optical lenses
[0076] Face number face shape Radius of curvature (R) Thickness (T) Refractive index (Nd) Abbe number (Vd) S1 aspherical 4.48 2.80 1.806 40.91 S2 aspherical 1.841 2.15 S3 spherical 29.71 7.40 1.871 40.73 S4 spherical -8.348 -0.09 S5 PL Infinity 2.60 S6 spherical 7.4090 2.00 1.593 68.34 S7 spherical -16.85 0.08 S8 spherical 9.1 1.70 1.593 68.34 S9 spherical -8.3566 2.72 1.946 17.94 S10 flat Infinity 0.20 S11 flat Infinity 0.40 1.517 64.20 S12 flat Infinity 1.45 S13 flat Infinity 0.40 1.517 64.20 S14 flat Infinity 0.13 IMA flat Infinity /
[0077] In Table 1, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens 11, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens 12, respectively, and so on. "STO" represents the aperture stop of the optical lens; the radius of curvature R represents the curvature of the corresponding lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat with an infinite radius of curvature. The thickness T represents the axial distance between the current surface and the next surface. Both the radius of curvature and the thickness are in millimeters (mm); the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current location is air and the refractive index is 1; the Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current location is air.
[0078] In this first embodiment, the first lens 11 is an aspherical lens, with both its object-side surface S1 and image-side surface S2 being aspherical. Its aspherical surface shape equation Z satisfies:
[0079] In Embodiment 1 of this application, the aspherical lens of the optical lens 100 satisfies the following formula:
[0080]
[0081] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; A, B, C, D, and E are the fourth, sixth, eighth, tenth, and twelfth order aspherical coefficients corresponding to the aspherical surface; k is the conic coefficient; and the units of Z, r, and c are all mm.
[0082] Table 2 Aspherical coefficients of optical lenses
[0083] Face number K A B C D E S1 -1.24 -5.6E-04 -1.1E-04 -2.5E-06 2.3E-07 7.1E-09 S2 -0.69 -7.2E-03 -9.7E-04 -2.6E-04 1.0E-04 -1.6E-05
[0084] In Table 2, -5.6E-04 indicates that the coefficient A for surface number S1 is -5.6 * 10. -4 And so on.
[0085] Furthermore, several performance tests were conducted on the optical lens 100 provided in Embodiment 1, and the specific test results are as follows:
[0086] Figure 2 This is a ray fan diagram of an optical lens provided in Embodiment 1 of this application. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 2 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 2 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens 100 provided in Embodiment 1 to form a clear image across the entire wavelength range.
[0087] Figure 3 This is an axial aberration curve diagram of an optical lens provided in Embodiment 1 of this application. Figure 3 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 3 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.02 mm, +0.02 mm), indicating that the spherical aberration of the optical lens 100 provided in Embodiment 1 of this application is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.
[0088] Figure 4 The field curvature distortion diagram of an optical lens provided in Embodiment 1 of this application is as follows: Figure 4 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 4 As can be seen, the optical lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 656nm, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.
[0089] In summary, the optical lens provided in Embodiment 1 of this application adopts a 5-element structure. By adjusting the lens shape, lens material combination, and different combinations of optical power, it can achieve clear imaging within a temperature range of -40℃ to +85℃. The aperture number of this lens is F1.55 or lower, which can meet the imaging needs of darker environments. Through the reasonable configuration of the optical power combination between the lens elements, the lens produces clear images and can be matched with imaging chips with more than 5 million pixels. It achieves the technical effects of high pixel count, miniaturization, high definition, large aperture, weak ghosting, and a total length of less than 24mm, which greatly reduces costs and is suitable for video recording fields such as action cameras and vehicle cameras that are subject to harsh environments.
[0090] Example 2
[0091] Figure 5 This is a schematic diagram of the structure of an optical lens provided in Embodiment 2 of this application. Figure 5 As shown, the optical lens 200 provided in Embodiment 2 of this application includes a first lens 21, a second lens 22, an aperture stop STO, a third lens 23, a fourth lens 24, and a fifth lens 25 arranged sequentially along the optical axis from the object plane to the image plane. Along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is the object-side surface, and the surface of the lens near the image plane is the image-side surface. The first lens 21 has negative optical power, its object-side surface is convex, and its image-side surface is concave. The second lens 22 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The third lens 23 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fourth lens 24 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fifth lens 25 has negative optical power, its image-side surface is concave, and its image-side surface is flat.
[0092] A flat glass CG is positioned in the optical path between the fifth lens 25 and the image plane M2. The flat glass CG protects the photosensitive chip in the imaging sensor. The imaging chip converts the light signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.
[0093] As one possible implementation method, please refer to [reference]. Figure 5 Table 3 shows the optical physical parameters of the first lens 21 to the fifth lens 25 in an optical lens 200 provided in Embodiment 2 of this application. The units for the radius of curvature R and thickness d are millimeters (mm). Table 4 shows the aspherical coefficient values of the aspherical lenses in the optical lens 200 provided in Embodiment 2 of this application.
[0094] Table 3 Design values of optical physical parameters of optical lenses
[0095]
[0096]
[0097] In Table 3, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens 21, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens 22, respectively, and so on. "STO" represents the aperture stop of the optical lens; the radius of curvature R represents the curvature of the corresponding lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat with an infinite radius of curvature. The thickness T represents the axial distance between the current surface and the next surface. Both the radius of curvature and the thickness are in millimeters (mm); the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current location is air and the refractive index is 1; the Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current location is air.
[0098] In this second embodiment, the first lens 21 is an aspherical lens, with both its object-side surface S1 and image-side surface S2 being aspherical. Its aspherical surface shape equation Z satisfies:
[0099] In Embodiment 2 of this application, the aspherical lens of the optical lens 200 satisfies the following formula:
[0100]
[0101] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; A, B, C, D, and E are the fourth, sixth, eighth, tenth, and twelfth order aspherical coefficients corresponding to the aspherical surface; k is the conic coefficient; and the units of Z, r, and c are all mm.
[0102] Table 4 Aspherical coefficient of optical lenses
[0103] Face number K A B C D E S1 -1.73 4.7E-04 -1.1E-04 -4.1E-06 2.3E-07 7.9E-09 S2 -0.73 -5.7E-03 -8.2E-04 -3.2E-04 1.1E-04 -1.6E-05
[0104] In Table 4, 4.7E-04 indicates that the coefficient A for surface number S1 is 4.7 * 10. -4 And so on.
[0105] Furthermore, several performance tests were conducted on the optical lens 200 provided in Embodiment 2, and the specific test results are as follows:
[0106] Figure 6 This is a ray fan diagram of an optical lens provided in Embodiment 2 of this application. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 6 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 6 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens 200 provided in Embodiment 2 to form a clear image across the entire wavelength range.
[0107] Figure 7 This is an axial aberration curve diagram of an optical lens provided in Embodiment 2 of this application. Figure 7 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 7 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.02 mm, +0.02 mm), indicating that the spherical aberration of the optical lens 200 provided in Embodiment 2 of this application is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.
[0108] Figure 8 This is a field curvature distortion diagram of an optical lens provided in Embodiment 2 of this application, such as... Figure 8 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 8As can be seen, the optical lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 656nm, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.
[0109] In summary, the optical lens provided in Embodiment 2 of this application adopts a 5-element structure. By adjusting the lens shape, lens material combination, and different combinations of optical power, it can achieve clear imaging within a temperature range of -40℃ to +85℃. The aperture number of this lens is F1.55 or lower, which can meet the imaging needs of darker environments. Through reasonable configuration of the optical power combination between the lenses, this lens produces clear images and can be matched with imaging chips with more than 5 million pixels. It achieves the technical effects of high pixel count, miniaturization, high definition, large aperture, weak ghosting, and a total length of less than 24mm, which greatly reduces costs and is suitable for video fields such as action cameras and vehicle cameras that are subject to harsh environments.
[0110] Example 3
[0111] Figure 9 This is a schematic diagram of the structure of an optical lens provided in Embodiment 3 of this application. Figure 9 As shown, the optical lens 300 provided in Embodiment 3 of this application includes a first lens 31, a second lens 32, an aperture stop STO, a third lens 33, a fourth lens 34, and a fifth lens 35 arranged sequentially along the optical axis from the object plane to the image plane. Along the optical axis from the object plane to the image plane, the surface of the lens facing the object plane is the object-side surface, and the surface of the lens near the image plane is the image-side surface. The first lens 31 has negative optical power, its object-side surface is convex, and its image-side surface is concave. The second lens 32 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The third lens 33 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fourth lens 34 has positive optical power, its object-side surface is convex, and its image-side surface is convex. The fifth lens 35 has negative optical power, its image-side surface is concave, and its image-side surface is flat.
[0112] A flat glass CG is positioned in the optical path between the fifth lens 35 and the image plane M2. The flat glass CG protects the photosensitive chip in the imaging sensor. The imaging chip converts the light signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.
[0113] As one possible implementation method, please refer to [reference]. Figure 9 Table 5 shows the optical physical parameters of the first lens 31 to the fifth lens 35 in an optical lens 300 provided in Embodiment 3 of this application. The units for the radius of curvature R and thickness d are millimeters (mm). Table 6 shows the aspherical coefficient values of the aspherical lenses in the optical lens 300 provided in Embodiment 3 of this application.
[0114] Table 5 Design values of optical physical parameters for optical lenses
[0115]
[0116]
[0117] In Table 5, the surface numbers are assigned according to the surface sequence of each lens. For example, surfaces S1 and S2 are the object-side and image-side surfaces of the first lens 31, respectively; surfaces S3 and S4 are the object-side and image-side surfaces of the second lens 32, respectively, and so on. "STO" represents the aperture stop of the optical lens; the radius of curvature R represents the curvature of the corresponding lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat with an infinite radius of curvature. The thickness T represents the central axial distance between the current surface and the next surface. Both the radius of curvature and the thickness are in millimeters (mm); the refractive index Nd represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number Vd represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air.
[0118] In this third embodiment, the first lens 31 is an aspherical lens, with both its object-side surface S1 and image-side surface S2 being aspherical. Its aspherical surface shape equation Z satisfies:
[0119] In Embodiment 3 of this application, the aspherical lens of the optical lens 300 satisfies the following formula:
[0120]
[0121] Where Z is the axial distance from the vertex of the surface at a position perpendicular to the optical axis and at a height of r along the optical axis; c represents the curvature at the vertex of the aspherical surface; A, B, C, D, and E are the fourth, sixth, eighth, tenth, and twelfth order aspherical coefficients corresponding to the aspherical surface; k is the conic coefficient; and the units of Z, r, and c are all mm.
[0122] Table 6 Aspherical coefficients of optical lenses
[0123] Face number K A B C D E S1 -1.23 -6.5E-04 -1.3E-04 -1.8E-06 2.3E-07 6.5E-09 S2 -0.70 -8.1E-03 -9.3E-04 -2.6E-04 1.0E-04 -1.6E-05
[0124] In Table 6, -6.5E-04 indicates that the coefficient A of surface number S1 is -6.5*10-4, and so on.
[0125] Furthermore, several performance tests were conducted on the optical lens 300 provided in Embodiment 3, and the specific test results are as follows:
[0126] Figure 10 This is a ray fan pattern of an optical lens provided in Embodiment 3 of this application. Ray fan patterns are one of the commonly used evaluation methods by optical designers. For example... Figure 10 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 10 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens 300 provided in Embodiment 3 to form a clear image across the entire 300-wavelength band.
[0127] Figure 11 This is an axial aberration curve diagram of an optical lens provided in Embodiment 3 of this application. Figure 11 As shown, the vertical direction represents the normalized aperture, with 0 indicating the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of system imaging, determined by... Figure 11 It can be seen that the axial aberrations of the normalized apertures of different wavelengths from 0 to 1.0 are all controlled within the range of (-0.02 mm, +0.02 mm), indicating that the spherical aberration of the optical lens 300 provided in Embodiment 3 of this application is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.
[0128] Figure 12 This is a field curvature distortion diagram of an optical lens provided in Embodiment 3 of this application, such as... Figure 12 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan(Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 12 As can be seen, the optical lens provided in this embodiment effectively controls the field curvature of light from wavelengths of 436nm to 656nm, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.
[0129] In summary, the optical lens provided in Embodiment 3 of this application adopts a 5-element structure. By adjusting the lens shape, lens material combination, and different combinations of optical power, it can achieve clear imaging within a temperature range of -40℃ to +85℃. The aperture number of this lens is F1.55 or lower, which can meet the imaging needs of darker environments. Through reasonable configuration of the optical power combination between the lens elements, this lens produces clear images and can be matched with imaging chips with more than 5 million pixels. It achieves the technical effects of high pixel count, miniaturization, high definition, large aperture, weak ghosting, and a total length of less than 24mm, greatly reducing costs. It is suitable for video recording fields such as action cameras and vehicle cameras that are subject to harsh environments.
[0130] In summary, the optical physical parameters of the first to fifth lenses in Embodiments 1, 2 and 3 of this application are shown in Table 7.
[0131] Table 7 Design values of optical physical parameters for optical lenses
[0132] Example 1 Example 2 Example 3 lower limit upper limit TTL / H 8.309 8.312 8.317 8.0 8.5 TTL / F 5.427 5.396 5.425 5.5 BFL / F 0.583 0.580 0.601 0.5 ENPD / TTL 0.120 0.120 0.120 0.1 f1 / F -1.666 -1.722 -1.630 -2.0 0.0 f2 / F 1.856 1.883 1.852 0.0 2.0 f3 / F 2.024 1.999 2.055 1.8 3.0 f4 / F 1.723 1.690 1.720 0.0 2.0 f5 / F -1.978 -2.023 -2.060 -3.0 0.0 f45 / F 9.103 7.531 7.677 7.0 10.0 |f4 / f5| 0.871 0.835 0.835 0.5 1.5 |f56 / F| 9.103 7.531 7.677 7.0 10.0 Vd4 / Vd5 3.809 3.809 3.809 3.000 3.5 Nd4 / Nd5 0.819 0.819 0.819 0.800 0.9 R1 / (R2+d1) 0.965 0.931 0.965 0.800 1.2 R5 / F 1.680 1.719 1.728 1.600 R1 / F 1.016 0.987 1.008 0.500 1.5
[0133] Note that the above description is merely a preferred embodiment and the technical principles employed in this application. Those skilled in the art will understand that this utility model is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the protection scope of this utility model. Therefore, although the utility model has been described in detail through the above embodiments, it is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this utility model, and the scope of this utility model is determined by the scope of the appended claims.
Claims
1. An optical lens characterized in that, It includes a first lens, a second lens, an aperture stop, a third lens, a fourth lens, and a fifth lens arranged sequentially along the optical axis from the object plane to the image plane; Along the optical axis from the object plane to the image plane, The first lens has negative optical power, and its object side is convex while its image side is concave. The second lens has positive optical power, and its object side is convex, as is its image side; The third lens has positive optical power, and its object side is convex, as is its image side; The fourth lens has positive optical power, and its object side is convex, as is its image side; The fifth lens has negative optical power, and its image-side surface is concave while its image-side surface is flat.
2. The optical lens of claim 1, wherein, The total optical length TTL of the optical lens and the image height H corresponding to the maximum field of view of the optical lens satisfy the following relationship: 8 < TTL / H < 8.
5.
3. The optical lens of claim 1, wherein, The total focal length F of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: TTL / F < 5.
5.
4. The optical lens of claim 1, wherein, The optical back focal length (BFL) of the optical lens and the total optical length (TTL) of the optical lens satisfy the condition: BFL / TTL > 0.
5.
5. The optical lens of claim 1, wherein, The entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: ENPD / TTL > 0.
1.
6. The optical lens of claim 1, wherein, The focal lengths f1, f2, f3, f4, and f5 of the first lens, the second lens, the third lens, and the fifth lens respectively satisfy the following relationship with the total focal length F of the optical lens: -2 <f1 / F<0;0<f2 / F<2;1.8<f3 / F<3;0<f4 / F<2;-3<f5 / F<0。 7. The optical lens of claim 1, wherein, The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy the following condition: 0.5 < |f4 / f5| < 1.5; The fourth lens and the fifth lens form a cemented lens, and the focal length f45 of the cemented lens and the total focal length F of the optical lens satisfy the following condition: 7≤|f45 / F|≤10.
8. The optical lens of claim 1, wherein, The refractive index Nd1 of the first lens satisfies: Nd1≥1.75; The Abbe number Vd4 and refractive index Nd4 of the fourth lens and the Abbe number Vd5 and refractive index Nd5 of the fifth lens satisfy the following conditions: 3 < Vd4 / Vd5 < 3.5; 0.8 < Nd4 / Nd5 < 0.
9.
9. The optical lens of claim 1, wherein, The central radius of curvature R1 of the object side of the first lens, the central radius of curvature R2 of the image side of the first lens, and the central thickness d1 of the first lens satisfy the following condition: 0.8≤R1 / (R2+d1)≤1.
2.
10. The optical lens of claim 1, wherein, The central radius of curvature R1 of the first lens surface and the total focal length F of the optical lens satisfy the following relationship: 0.5 < R1 / F < 1.5; The central radius of curvature R5 of the side surface of the third lens satisfies the following relationship with the total focal length F of the optical lens: R5 / F > 1.6.