Imaging lens and electronic equipment

Abstract

The utility model discloses an imaging lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged along an optical axis from an object side to an image side. The first lens has a positive refractive index, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a plane; the second lens has a positive refractive index, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; and the like. According to the utility model, the lens adopts six pieces of grinding spherical glass, the light path structure is simple, the assembly is facilitated, and the light assembly yield is high; the light transmission FNO of the lens reaches 2.0, the imaging is excellent, no obvious purple edge and chromatic dispersion exist, the image quality is clear and bright, the lens can adapt to a target surface with two millions of pixels, and the pixel size is 2 microns; the wavelength range of the lens is 435-650 [mu] m; application requirements of special scenes are met, and all-weather clear imaging requirements are covered; the lens meets the temperature drift requirement from-40 DEG C to 85 DEG C, and athermalization design is achieved.

Description

Technical Field

[0001] This utility model relates to the field of imaging lens technology, and in particular to an imaging lens and electronic device. Background Technology

[0002] Existing imaging lenses, especially automotive-grade lenses, are mainly used for applications such as autonomous driving forward vision and traffic light recognition. However, most existing imaging lenses suffer from one or more of the following drawbacks:

[0003] Firstly, existing lenses have low light transmission and low energy utilization, which cannot meet customer needs;

[0004] Secondly, existing lenses cannot pass harsh environment tests, such as rain exposure.

[0005] Thirdly, the lens uses a lot of lens elements, which can easily reduce the optical assembly yield. It also has the disadvantages of being large in size and heavy in weight.

[0006] Fourth, in automotive lens usage scenarios, the lens is prone to focus loss under high and low temperature conditions, making it difficult to meet the requirement of maintaining clear imaging under large temperature ranges. Utility Model Content

[0007] In view of this, the purpose of this utility model is to provide an imaging lens and an electronic device. This lens can at least solve one of the technical shortcomings mentioned in the background art.

[0008] According to one aspect of the present invention, an imaging lens is provided, characterized in that it comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side;

[0009] The first lens has a positive refractive index, the object side of the first lens is convex, and the image side of the first lens is flat.

[0010] The second lens has a positive refractive index, the object side of the second lens is convex, and the image side of the second lens is concave.

[0011] The third lens has a negative refractive index, the object side of the third lens is convex, and the image side of the third lens is concave.

[0012] The fourth lens has a negative refractive index, and the object-side surface of the fourth lens is concave, and the image-side surface of the fourth lens is concave.

[0013] The fifth lens has a positive refractive index, and the object-side surface of the fifth lens is convex, as is the image-side surface of the fifth lens.

[0014] The sixth lens has a positive refractive index, the object side of the sixth lens is convex, and the image side of the sixth lens is either convex or flat.

[0015] The lens uses six polished spherical glass elements, resulting in a simple optical path structure that facilitates assembly and achieves a high optical assembly yield. With an FNO of 2.0, the lens delivers excellent imaging with no noticeable purple fringing or chromatic aberration, producing clear and bright images. It is compatible with 20-megapixel targets with a pixel size of 2µm. The lens has a wavelength range of 435µm to 650µm, meeting the application requirements of special scenarios and covering all-weather clear imaging needs. The lens also meets temperature drift requirements from -40℃ to 85℃, achieving a heat-free design.

[0016] According to another aspect of the present invention, an electronic device is provided, comprising an imaging lens as described above; and an image sensor configured to receive an image formed by the imaging lens. In this technical solution, the advantages of the electronic device depend on the imaging lens, which will not be elaborated upon here. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of the optical system of the lens in Example 1.

[0019] Figure 2 The MTF diagram in the visible light 435nm-650nm band is shown in Example 1.

[0020] Figure 3 This is the distortion diagram in the visible light 435nm-650nm band of Example 1.

[0021] Figure 4 This is the longitudinal color difference curve in the visible light 435nm-650nm band of Example 1.

[0022] Figure 5 This is the on-axis chromatic difference curve in the visible light 435nm-650nm band of Example 1.

[0023] Figure 6 This is a relative illuminance diagram in the visible light 435nm-650nm band of Example 1.

[0024] Figure 7 This is a structural diagram of the optical system of the lens in Example 2.

[0025] Figure 8 This is the MTF diagram in the visible light 435nm-650nm band in Example 2.

[0026] Figure 9 This is the distortion diagram in the visible light 435nm-650nm band of Example 2.

[0027] Figure 10 This is the longitudinal color difference curve in the visible light 435nm-650nm band of Example 2.

[0028] Figure 11 This is the on-axis chromatic difference curve in the visible light 435nm-650nm band in Example 2.

[0029] Figure 12 This is a relative illuminance diagram in the visible light 435nm-650nm band of Example 2.

[0030] Figure 13 This is a structural diagram of the optical system of the lens in Example 3.

[0031] Figure 14 The MTF diagram in the visible light 435nm-650nm band is shown in Example 3.

[0032] Figure 15 This is the distortion diagram in the visible light 435nm-650nm band of Example 3.

[0033] Figure 16 This is the longitudinal color difference curve in the visible light 435nm-650nm band of Example 3.

[0034] Figure 17 This is the on-axis chromatic difference curve in the visible light 435nm-650nm band of Example 3.

[0035] Figure 18 This is the relative illuminance diagram in the visible light 435nm-650nm band of Example 3.

[0036] Figure 19 This is a schematic diagram of the structure of the electronic device of this utility model.

[0037] L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; ST, aperture stop; CG, protective glass; IR, filter; IMA, imaging plane. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are only for illustrating the present invention and do not limit the scope of the present invention. Similarly, the following embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0039] The purpose of this invention is to provide an imaging lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side.

[0040] The first lens has a positive refractive index, the object side of the first lens is convex, and the image side of the first lens is flat.

[0041] The second lens has a positive refractive index, the object side of the second lens is convex, and the image side of the second lens is concave.

[0042] The third lens has a negative refractive index, the object side of the third lens is convex, and the image side of the third lens is concave.

[0043] The fourth lens has a negative refractive index, and the object-side surface of the fourth lens is concave, and the image-side surface of the fourth lens is concave.

[0044] The fifth lens has a positive refractive index, and the object-side surface of the fifth lens is convex, as is the image-side surface of the fifth lens.

[0045] The sixth lens has a positive refractive index, the object side of the sixth lens is convex, and the image side of the sixth lens is either convex or flat.

[0046] Specifically, in Embodiments 1 and 3, the image-side surface of the sixth lens is planar. In Embodiment 2, the image-side surface of the sixth lens is convex, and an aperture stop is provided between the third and fourth lenses.

[0047] Among them, reference Figure 1 , Figure 7 , Figure 13 As shown in the figure. The first lens is labeled L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, the twelfth lens L12, the aperture stop is labeled ST, the filter is labeled IR, the protective glass is labeled CG, and the imaging plane is labeled IMA.

[0048] As one embodiment, the lens satisfies the following relationship: Nd1 > 1.70; where Nd1 is the refractive index of the first lens. The beneficial effect of this embodiment is that the first lens is made of a high-refractive-index material with excellent mechanical properties and chemical stability. This selection ensures a large optical aperture ratio, which is beneficial for reducing the front aperture of the optical system, thereby achieving lens miniaturization. It also helps the optical lens cope with complex environments, such as automotive pre-installed applications.

[0049] As one embodiment, the lens satisfies the following relationship: Nd2 > 1.70; Vd2 > 45; where Nd2 is the refractive index of the second lens and Vd2 is the Abbe coefficient of the second lens. The beneficial effect of this embodiment is that the use of a high refractive index material in the second lens effectively controls the light refraction angle on the second lens, making the light propagation path inside the lens more compact and reducing excessive light divergence or convergence, thereby effectively improving image quality and increasing the lens's optical assembly yield.

[0050] As one embodiment, the lens satisfies the following relationships: Nd3 ≥ 1.85; Vd3 < 25; where Nd3 is the refractive index of the third lens and Vd3 is the Abbe coefficient of the third lens. The beneficial effect of this embodiment is that the third lens uses a high-refractive-index, low-dispersion glass material. By satisfying the above parameters, it has a significant effect on correcting second-order chromatic aberration, thereby significantly improving image quality. The high refractive index optimizes the propagation path of light within the lens, while the low dispersion reduces chromatic aberration between different wavelengths of light, resulting in clearer and sharper images. Through this design, the optical system can maintain excellent imaging performance at different wavelengths, which is crucial for improving overall optical quality and image accuracy.

[0051] As one embodiment, the lens satisfies the following relationships: 1.50 < Nd4 < 1.65; 55 < Vd4 < 65; where Nd4 is the refractive index of the fourth lens and Vd4 is the Abbe coefficient of the fourth lens. The beneficial effect of this embodiment is that by satisfying the above parameters, more effective aberration correction can be achieved without increasing the number of lenses. This material combination helps reduce common aberrations such as chromatic aberration and improves the overall imaging quality of the optical system.

[0052] As one embodiment, the lens satisfies the following relationships: 1.55 < Nd5 < 1.65; 70 < Vd5 < 75; dn / dT < -6*10E-6 within a temperature range of -40℃ to 105℃; where Nd5 is the refractive index of the fifth lens, Vd5 is the Abbe coefficient of the fifth lens, and dn / dT is the temperature coefficient of refractive index of the material used in the fifth lens. The beneficial effects of this embodiment are: by satisfying the above parameters, chromatic aberration can be effectively reduced, image quality improved, and light of different wavelengths can be more accurately focused on the same focal point. The fifth lens uses a material with a negative temperature coefficient of refractive index, which can effectively balance temperature drift and achieve calorific value reduction.

[0053] As one embodiment, the lens satisfies the following relationships: 0.95 < Nd4 / Nd5 < 1.05; Vd5 - Vd4 > 7.5; where the fourth and fifth lenses are a cemented lens group, Nd4 is the refractive index of the fourth lens, Vd4 is the Abbe coefficient of the fourth lens, Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe coefficient of the fifth lens. The beneficial effects of this embodiment are: the cemented lens group utilizes the different dispersion characteristics of high-dispersion and low-dispersion materials, allowing light with different convergence positions to achieve a closer convergence point on the optical axis through mutual compensation, thereby significantly reducing on-axis chromatic aberration and improving the imaging quality of the optical system. Furthermore, by selecting a combination of high-dispersion and low-dispersion materials, the dispersion characteristics of the two materials can compensate for each other, effectively reducing magnification chromatic aberration and improving the sharpness and accuracy of the image.

[0054] As one embodiment, the lens satisfies the following relationship: Nd6 > 1.8; Vd6 < 25.5; where Nd6 is the refractive index of the sixth lens and Vd6 is the Abbe coefficient of the sixth lens. The beneficial effect of this embodiment is that the sixth lens uses a high-refractive-index, low-dispersion material, which can achieve the required optical performance within a smaller physical size, thereby helping to reduce the radius of the rear end of the lens, making the optical system more compact and easier to integrate into miniaturized devices.

[0055] In summary, the beneficial effects of this utility model are as follows:

[0056] Firstly, by reasonably controlling the positive and negative combinations of the optical power of each lens, the low-order aberrations of the lens can be effectively balanced, while reducing the sensitivity of the lens to tolerances, maintaining the miniaturization of the lens while ensuring the image quality of the lens.

[0057] Secondly, the lens has an FNO of 2.0, resulting in excellent image quality with no obvious purple fringing or chromatic aberration. The image quality is clear and bright, and it can be adapted to a 20-megapixel target surface with a pixel size of 2um.

[0058] Thirdly, the lens wavelength range is 435um to 650um; it meets the application requirements of special scenarios and covers the need for clear imaging in all weather conditions;

[0059] Fourth, the lens meets the temperature drift requirement from -40℃ to 85℃, achieving a heat-free design;

[0060] Fifth, the lens uses six ground spherical glass elements, which has a simple optical path structure, is easy to assemble, and has a high optical assembly yield. The lens structure can be described as six elements in five groups. The design uses relatively inexpensive optical materials, balancing cost, yield, and optical performance.

[0061] The present invention will be described in more detail below with reference to the following tables. It should be noted that the following tables are only specific embodiments of the present invention, and not limiting examples.

[0062] For ease of description, in the table, surface number 1 and surface number 2 are the object-side and image-side surfaces of the first lens, respectively; surface number 3 and surface number 4 are the object-side and image-side surfaces of the second lens, respectively; surface number 5 and surface number 6 are the object-side and image-side surfaces of the third lens, respectively; surface number 7 is the surface of the aperture stop; surface number 8 and surface number 9 are the object-side and image-side surfaces of the fourth lens, respectively; surface number 9 and surface number 10 are the object-side and image-side surfaces of the fifth lens, respectively; surface number 11 and surface number 12 are the object-side and image-side surfaces of the sixth lens, respectively; surface number 13 and surface number 14 are the object-side and image-side surfaces of the filter, respectively; surface number 15 and surface number 16 are the object-side and image-side surfaces of the protective glass, respectively; and surface number 17 is the surface of the imaging plane.

[0063] Please refer to the optical structure of Example 1. Figure 1 The specific parameters of this embodiment 1 are shown in Table 1 below. In this embodiment 1, the lens focal length f = 28.4 mm, the light transmission FNO = 2.0, the field of view FOV = 18.28°, the target surface size IMH = 8.81 mm, and the total length TTL = 33.32 mm.

[0064] Table 1 - Lens Parameter Table for Example 1

[0065] Face number type radius of curvature thickness Material Refractive index Abbe coefficient lens focal length 1 First lens 20.313 3.500 Glass 1.75 51 27.10 2 219.728 1.138 3 Second lens 12.616 3.850 Glass 1.73 54.7 24.40 4 37.500 0.428 5 Third lens 107.962 3.770 Glass 1.85 23.8 -9.50 6 7.416 0.898 7 aperture Infinity 1.533 8 Fourth lens -14.373 1.000 Glass 1.55 58.4 -7.46 9 Fifth lens 5.946 2.780 Glass 1.57 71.3 7.68 10 -13.856 0.182 11 Sixth lens 28.851 1.830 Glass 1.81 25.4 31.13 12 -195.913 0.500 13 Filter Infinity 0.300 Glass 1.52 64.2 14 Infinity 10.608 15 Protective glass Infinity 0.500 Glass 1.52 64.2 16 Infinity 0.500 17 Imaging surface

[0066] According to Table 1, the conditional expression of Embodiment 1 of this utility model can be read as follows:

[0067] (1) The refractive index of the first lens is Nd1 = 1.75;

[0068] (2) The refractive index of the second lens is Nd2 = 1.73; the Abbe coefficient of the second lens is Vd2 = 54.7;

[0069] (3) The refractive index of the third lens is Nd3 = 1.85; the Abbe coefficient of the third lens is Vd3 = 23.8;

[0070] (4) The refractive index of the fourth lens is Nd4 = 1.55; the Abbe coefficient of the fourth lens is Vd4 = 58.4;

[0071] (5) The refractive index of the fifth lens is Nd5 = 1.57; the Abbe coefficient of the fifth lens is Vd5 = 71.3;

[0072] (6) The refractive index ratio of the fourth lens and the fifth lens is Nd4 / Nd5 = 0.99; the Abbe coefficient difference between the fourth lens and the fifth lens is Vd5-Vd4 = 12.9;

[0073] (7) The refractive index of the sixth lens is Nd6 = 1.81; the Abbe coefficient of the sixth lens is Vd6 = 25.4.

[0074] Please refer to the optical structure of Example 2. Figure 7 The specific parameters of this embodiment 2 are shown in Table 2 below. In this embodiment 2, the lens focal length f = 28.32mm, the light transmission FNO = 2.0, the field of view FOV = 18.27°, the target surface size IMH = 8.81mm, and the total length TTL = 31.68mm.

[0075] Table 2 - Lens Parameter Table for Example 2

[0076] Face number type radius of curvature thickness Material Refractive index Abbe coefficient lens focal length 1 First lens 20.63 2.70 Glass 1.77 49.60 26.61 2 Infinity 0.56 3 Second lens 12.30 3.73 Glass 1.74 52.70 23.55 4 36.01 0.46 5 Third lens 70.45 3.71 Glass 1.85 23.80 -9.73 6 7.25 1.03 7 aperture Infinity 2.27 8 Fourth lens -15.34 1.00 Glass 1.55 63.60 -10.30 9 Fifth lens 9.30 2.21 Glass 1.57 71.30 10.39 10 -14.93 1.47 11 Sixth lens 45.08 1.81 Glass 1.81 25.40 33.98 12 -69.59 0.50 13 Filter Infinity 0.30 Glass 1.52 64.20 14 Infinity 8.93 15 Protective glass Infinity 0.50 Glass 1.52 64.20 16 Infinity 0.50 17 Imaging surface Infinity

[0077] According to Table 2, the conditional expression of Embodiment 2 of this utility model can be read as follows:

[0078] (1) The refractive index of the first lens is Nd1 = 1.77;

[0079] (2) The refractive index of the second lens is Nd2 = 1.74; the Abbe coefficient of the second lens is Vd2 = 52.7;

[0080] (3) The refractive index of the third lens is Nd3 = 1.85; the Abbe coefficient of the third lens is Vd3 = 23.8;

[0081] (4) The refractive index of the fourth lens is Nd4 = 1.55; the Abbe coefficient of the fourth lens is Vd4 = 63.6;

[0082] (5) The refractive index of the fifth lens is Nd5 = 1.57; the Abbe coefficient of the fifth lens is Vd5 = 71.3;

[0083] (6) The refractive index ratio of the fourth lens and the fifth lens is Nd4 / Nd5 = 0.99; the Abbe coefficient difference between the fourth lens and the fifth lens is Vd5-Vd4 = 7.7;

[0084] (7) The refractive index of the sixth lens is Nd6 = 1.81; the Abbe coefficient of the sixth lens is Vd6 = 25.4.

[0085] Please refer to the optical structure of Example 3. Figure 13 The specific parameters of this embodiment 3 are shown in Table 3 below. In this embodiment 3, the lens focal length f = 28.42mm, the light transmission FNO = 2.0, the field of view FOV = 18.28°, the target surface size IMH = 8.81mm, and the total length TTL = 33mm.

[0086] Table 3 - Lens Parameter Table for Example 3

[0087] Face number type radius of curvature thickness Material Refractive index Abbe coefficient lens focal length 1 First lens 19.862 3.350 Glass 1.75 51 26.50 2 Infinity 0.921 3 Second lens 12.732 3.700 Glass 1.73 54.7 25.00 4 36.758 0.455 5 Third lens 93.722 3.970 Glass 1.85 23.8 -9.78 6 7.510 1.148 7 aperture Infinity 1.174 8 Fourth lens -14.355 1.000 Glass 1.55 63.4 -7.90 9 Fifth lens 6.456 2.600 Glass 1.57 71.3 8.12 10 -14.022 0.312 11 Sixth lens 27.987 1.940 Glass 1.81 25.4 34.52 12 Infinity 0.500 13 Filter Infinity 0.300 Glass 1.52 64.2 14 Infinity 10.620 15 Protective glass Infinity 0.500 Glass 1.52 64.2 16 Infinity 0.500 17 Imaging surface

[0088] According to Table 2, the conditional expression of Embodiment 2 of this utility model can be read as follows:

[0089] (1) The refractive index of the first lens is Nd1 = 1.75;

[0090] (2) The refractive index of the second lens is Nd2 = 1.73; the Abbe coefficient of the second lens is Vd2 = 54.7;

[0091] (3) The refractive index of the third lens is Nd3 = 1.85; the Abbe coefficient of the third lens is Vd3 = 23.8;

[0092] (4) The refractive index of the fourth lens is Nd4 = 1.55; the Abbe coefficient of the fourth lens is Vd4 = 63.4;

[0093] (5) The refractive index of the fifth lens is Nd5 = 1.57; the Abbe coefficient of the fifth lens is Vd5 = 71.3;

[0094] (6) The refractive index ratio of the fourth lens and the fifth lens is Nd4 / Nd5 = 0.99; the Abbe coefficient difference between the fourth lens and the fifth lens is Vd5-Vd4 = 7.9;

[0095] (7) The refractive index of the sixth lens is Nd6 = 1.81; the Abbe coefficient of the sixth lens is Vd6 = 25.4.

[0096] Table 4 - Lens Parameters

[0097] Parameter Description parameter Example 1 Example 2 Example 3 focal length f 28.4 28.32 28.42 Like Gao H 9.25 9.25 8.81 Optical back focal length BFL 12.41 10.73 12.42 Overall optical length TTL 33.32 31.68 33.00 Tongguang FNO FNO 2 2 2 Field of view (FOV) FOV 18.28 18.27 18.28

[0098] The following is an explanation of the various figures in Examples 1 to 3:

[0099] Example 1

[0100] Figure 2The image shows the MTF (Mean Transmission Format) in the visible light band of 435nm-650nm in Example 1. As can be seen from the image, with a field of view (FOV) of 18.28° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at 250 lp / mm and greater than 0.5 at 125 lp / mm. This indicates that this example has high resolution and good imaging quality, especially in the mid- and high-frequency ranges.

[0101] Figure 3 This is the distortion diagram in the visible light 435nm-650nm band of Example 1. As can be seen from the diagram, the edge field-of-view distortion values ​​are all less than ±2%, indicating low optical distortion at large field-of-view angles, resulting in excellent imaging effect and high image fidelity.

[0102] Figure 4 This is the longitudinal chromatic aberration curve (magnification chromatic aberration diagram) in the visible light 435nm-650nm band of Example 1. As can be seen from the figure, the chromatic aberration represents the lens's chromatic aberration as the field of view changes. The five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 2.5µm. In such a large target surface and high-throughput optical system, the chromatic aberration is negligible, therefore it can be called "zero chromatic aberration".

[0103] Figure 5 This is the on-axis chromatic aberration curve in the visible light 435nm-650nm band of Example 1. As can be seen from the figure: the diagram shows the axial chromatic aberration of the lens as the aperture changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a color focus shift of less than 0.05mm across the entire field of view. It has good color reproduction, small chromatic aberration, and minimal blue-purple fringing.

[0104] Figure 6 This is the relative illumination diagram in the visible light 435nm-650nm band of Example 1. As can be seen from the diagram, the lens achieves a relative illumination greater than 75% while maintaining a target half-image height of 4.625.

[0105] Example 2

[0106] Figure 8The image shows the MTF (Mean Transformer Format) values ​​in the visible light band of 435nm-650nm in Example 2. As can be seen from the image, with a field of view (FOV) of 18.27° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.25 at 250 lp / mm and greater than 0.55 at 125 lp / mm, indicating that this example has high resolution and good imaging quality.

[0107] Figure 9 This is a distortion diagram in the visible light band of 435nm-650nm, as shown in Example 2. The diagram shows that the edge field-of-view distortion values ​​are all less than ±2%, indicating low optical distortion at large field-of-view angles, resulting in excellent imaging performance and high image fidelity.

[0108] Figure 10 This is the longitudinal chromatic aberration curve (magnification chromatic aberration diagram) in the visible light 435nm-650nm band of Example 2. The diagram shows the chromatic aberration of the lens as the field of view changes. The five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 6µm, slightly worse than in Example 1.

[0109] Figure 11 This is the on-axis chromatic aberration curve in the visible light 435nm-650nm band in Example 2. The graph shows the axial chromatic aberration of the lens as the aperture changes. The five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a chromatic focus shift of less than 0.06mm across the entire field of view. It exhibits good color reproduction, small chromatic aberration, and minimal blue-violet fringing.

[0110] Figure 12 The figure shows the relative illumination in the visible light band of 435nm-650nm in Example 2. As can be seen from the figure, the lens achieves a relative illumination greater than 70% while maintaining a target half-image height of 4.405.

[0111] Example 3

[0112] Figure 14 The image shows the MTF (Mean Transformer Format) values ​​in the visible light band of 435nm-650nm in Example 3. As can be seen from the image, with a field of view (FOV) of 18.28° and a target size (IMH) of 8.81mm, the MTF value is greater than 0.3 at a frequency of 250 lp / mm and greater than 0.55 at a frequency of 125 lp / mm. This indicates that this example has high resolution and good imaging quality.

[0113] Figure 15 This is the distortion diagram in the visible light 435nm-650nm band of Example 3. As can be seen from the diagram, the edge field-of-view distortion values ​​are all less than ±2%, indicating low optical distortion at large field-of-view angles, resulting in excellent imaging effect and high image fidelity.

[0114] Figure 16 In Example 3, the longitudinal chromatic aberration curve (magnification chromatic aberration diagram) in the visible light 435nm-650nm band represents the magnification chromatic aberration of the lens as the field of view changes. The five lines correspond to wavelengths of 0.435um, 0.51um, 0.55um, 0.61um, and 0.65um, respectively. The horizontal axis represents the magnification chromatic aberration value, and the vertical axis represents the normalized field of view angle. The longitudinal chromatic aberration (magnification chromatic aberration) across the entire field of view is less than 2um. In such a large target surface and large light transmission optical system, the magnification chromatic aberration is negligible, and therefore can be called "zero chromatic aberration".

[0115] Figure 17 This is the on-axis chromatic aberration curve in the visible light 435nm-650nm band of Example 3. As can be seen from the figure: the diagram shows the axial chromatic aberration of the lens as the aperture changes, where the five lines correspond to wavelengths of 0.435µm, 0.51µm, 0.55µm, 0.61µm, and 0.65µm, respectively. The horizontal axis represents the axial aberration value, and the vertical axis represents the normalized aperture. It can be seen that the lens has small chromatic aberration, high color reproduction, and a color focus shift of less than 0.05mm across the entire field of view.

[0116] Figure 18 The figure shows the relative illumination in the visible light band of 435nm-650nm in Example 3. As can be seen from the figure, the lens achieves a relative illumination greater than 60% while maintaining a target half-image height of 4.625.

[0117] On the other hand, now refer to Figure 19 A schematic diagram of the structure of electronic device A according to this utility model will be given. Figure 19 This is a schematic diagram of an electronic device (camera) for a photographic optical system, using any one of the imaging lenses according to Embodiments 1 to 3.

[0118] exist Figure 19 In the figures, reference numeral A2 indicates the main body of the electronic device, and reference numeral A1 indicates a camera optical system (interchangeable lens) including any of the imaging lenses according to Examples 1 to 3. Reference numeral A3 indicates an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built into the camera body A2 and receives light (optical image formed by the camera optical system A1) from the camera optical system A1 and performs photoelectric conversion.

[0119] By using the imaging lens according to any one of Embodiments 1 to 3 in an electronic device such as a digital still camera, an electronic device with high optical performance can be obtained.

[0120] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the following claims will be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. An imaging lens, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side; The first lens has a positive refractive index, the object side of the first lens is convex, and the image side of the first lens is flat. The second lens has a positive refractive index, the object side of the second lens is convex, and the image side of the second lens is concave. The third lens has a negative refractive index, the object side of the third lens is convex, and the image side of the third lens is concave. The fourth lens has a negative refractive index, and the object-side surface of the fourth lens is concave, and the image-side surface of the fourth lens is concave. The fifth lens has a positive refractive index, and the object-side surface of the fifth lens is convex, as is the image-side surface of the fifth lens. The sixth lens has a positive refractive index, the object side of the sixth lens is convex, and the image side of the sixth lens is either convex or flat.

2. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: Nd1 > 1.70; Wherein, Nd1 is the refractive index of the first lens.

3. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: Nd2 > 1.70; Vd2 > 45; Wherein, Nd2 is the refractive index of the second lens, and Vd2 is the Abbe coefficient of the second lens.

4. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: Nd3 ≥ 1.85; Vd3 < 25; Wherein, Nd3 is the refractive index of the third lens, and Vd3 is the Abbe coefficient of the third lens.

5. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: 1.50<Nd4<1.65; 55<Vd4<65; Wherein, Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe coefficient of the fourth lens.

6. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: 1.55 < Nd5 < 1.65; 70 < Vd5 < 75; within the temperature range of -40℃ to 105℃, dn / dT < -6*10E-6; where Nd5 is the refractive index of the fifth lens, Vd5 is the Abbe coefficient of the fifth lens, and dn / dT is the temperature coefficient of the refractive index of the material used for the fifth lens.

7. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: 0.95<Nd4 / Nd5<1.05; Vd5-Vd4>7.5; Wherein, the fourth lens and the fifth lens are a cemented lens group, Nd4 is the refractive index of the fourth lens, Vd4 is the Abbe coefficient of the fourth lens, Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe coefficient of the fifth lens.

8. An imaging lens as described in claim 1, characterized in that, The lens satisfies the following relationship: Nd6 > 1.8; Vd6 < 25.5; Wherein, Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe coefficient of the sixth lens.

9. An electronic device, characterized in that, An imaging lens according to any one of claims 1-8; and an image sensor configured to receive an image formed by the imaging lens.

Images