Optical lens and communication device

Abstract

This invention discloses an optical lens and a communication device, relating to the field of optical lens technology. The optical lens has an object side and an image side arranged opposite each other along the optical axis. The optical lens includes a first lens to an eighth lens arranged sequentially from the object side to the image side. The first to third lenses together form a first lens group with positive optical power. The fourth to eighth lenses together form a second lens group with positive optical power. The total optical length of the optical lens is TTL, where TTL ≤ 30mm. The diameter D1 of the first lens satisfies D1 ≤ 14mm. The imaging quality of the optical lens is greater than or equal to 50 megapixels. The technical solution provided by this invention divides eight lenses into two lens groups, both with positive optical power, limiting the total optical length and the diameter of the first lens. This ensures that the optical lens has a large image area and high pixel density, meeting the requirements for high-resolution shooting, while also adapting to the space requirements of miniaturized equipment installation.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and in particular to an optical lens and a communication device. Background Technology

[0002] The current video lens market exhibits several trends: continued market growth, diversified product forms, increasing emphasis on high definition and intelligence, and segmentation of application scenarios. As application scenarios and demands continue to rise, the current resolution of most video lenses is no longer sufficient to meet requirements.

[0003] Currently, the 720P and 1080P resolution of lenses is insufficient for the image quality requirements of 4K and 8K. Furthermore, fixed-focus lenses lack optical zoom, only cropping the image for magnification, which further reduces the pixel count and results in blurry images. In addition, current mainstream video lenses are long and have large apertures, making them bulky and hindering the miniaturization of system equipment. Summary of the Invention

[0004] The main objective of this invention is to provide an optical lens and a communication device, which aims to provide an optical lens with small size and high resolution.

[0005] To achieve the above objectives, the present invention proposes an optical lens having an object side and an image side arranged opposite each other along the optical axis. The optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side to the image side. The first lens, the second lens, and the third lens together form a first lens group, and the optical power of the first lens group is positive. The fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens together form a second lens group, and the optical power of the second lens group is positive. The total optical length of the optical lens is TTL, where TTL ≤ 30 mm. The diameter D1 of the first lens satisfies: D1 ≤ 14 mm. The imaging quality of the optical lens is greater than or equal to 50 million pixels.

[0006] In one embodiment, the optical power of the fourth lens and the eighth lens is positive; The first lens, the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens have negative optical power.

[0007] In one embodiment, the fourth lens, the fifth lens, and the sixth lens are cemented together.

[0008] In one embodiment, the fourth lens, the fifth lens, and the sixth lens are glass lenses. The refractive index of the fourth lens is N4, and the Abbe number of the fourth lens is V4, where 1.45≤N4≤1.5 and 80≤V4≤85. The refractive index of the fifth lens is N5, and the Abbe number of the fourth lens is V5, where 1.60≤N5≤1.65 and 40≤V5≤50. The refractive index of the sixth lens is N6, and the Abbe number of the fourth lens is V6, where 1.40≤N6≤1.50 and 90≤V6≤96.

[0009] In one embodiment, the focal length of the optical lens is F, the focal length of the first lens group is F1, and the focal length of the second lens group is F2. It satisfies: 1.8≤F1 / F≤2, 3.5≤F2 / F≤4.

[0010] In one embodiment, the focal length of the first lens is f1, and -0.8 ≤ f1 / F1 ≤ -0.7; The focal length of the second lens is f2, -4.8≤f2 / F1≤-4.3; The focal length of the third lens is f3, and 0.6 ≤ f3 / F1 ≤ 0.9; The focal length of the fourth lens is f4, and 0.4 ≤ f4 / F2 ≤ 0.7; The focal length of the fifth lens is f5, and -0.6 ≤ f5 / F2 ≤ -0.3; The focal length of the sixth lens is f6, and -1.6 ≤ f6 / F2 ≤ -1.3; The focal length of the seventh lens is f7, and 13.5≤f7 / F2≤-12; The focal length of the eighth lens is f8, and 12≤f8 / F2≤22.

[0011] In one embodiment, the optical lens further includes: An aperture stop is positioned between the first lens group and the second lens group; A filter is disposed on the image side of the eighth lens.

[0012] In one embodiment, the aperture value of the optical lens is greater than or equal to 2.0 and less than or equal to 2.4; and / or, The aperture size of the aperture stop is D2, 6mm≤D2≤7mm; and / or, The distance between the first lens and the second lens is L1, where 3mm ≤ L1 ≤ 3.5mm; the distance between the third lens and the fourth lens is L2, where 2mm ≤ L2 ≤ 2.5mm.

[0013] In one embodiment, the angle between the principal ray of the optical lens and the image plane is CRA, -2.5°≤CRA≤2.5°; and / or, The optical distortion of the optical lens is less than 8%.

[0014] The present invention also proposes a communication device, including an optical lens.

[0015] The technical solution of the present invention configures eight lenses into two lens groups, both of which have positive optical power. Under the premise of limiting the total optical length and the diameter of the first lens, it ensures that the optical lens has a large image plane and high pixel imaging capability, which can meet the high resolution shooting requirements, while adapting to the installation space requirements of miniaturized equipment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the structure of an embodiment of the optical lens provided by the present invention; Figure 2 for Figure 1 Spatial frequency MTF diagram of a medium optical lens; Figure 3 for Figure 1 A dot diagram of a medium-sized optical lens; Figure 4 for Figure 1 Field curvature distortion diagram of a medium optical lens; Figure 5 for Figure 1 Relative illumination diagram of a medium optical lens.

[0018] Explanation of icon numbers: 100. Optical lens; 1. First lens group; 11. First lens; 12. Second lens; 13. Third lens; 2. Second lens group; 21. Fourth lens; 22. Fifth lens; 23. Sixth lens; 24. Seventh lens; 25. Eighth lens; 3. Aperture stop; 4. Filter.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] Currently, the 720P and 1080P resolution of lenses is insufficient for the image quality requirements of 4K and 8K. Furthermore, fixed-focus lenses lack optical zoom, only cropping the image for magnification, which further reduces the pixel count and results in blurry images. In addition, current mainstream video lenses are long and have large apertures, making them bulky and hindering the miniaturization of system equipment.

[0024] This invention proposes an optical lens.

[0025] Please see Figure 1In one embodiment of the present invention, the optical lens has an object side and an image side arranged opposite to each other along the optical axis. The optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side to the image side. The first lens, the second lens, and the third lens together form a first lens group, and the optical power of the first lens group is positive. The fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens together form a second lens group, and the optical power of the second lens group is positive. The total optical length of the optical lens is TTL, where TTL ≤ 30 mm. The diameter D1 of the first lens satisfies: D1 ≤ 14 mm. The imaging quality of the optical lens is greater than or equal to 50 million pixels.

[0026] In the technical solution of this invention, the optical axis is the reference center line connecting the centers of all lenses in the lens; the object side is the side of the lens facing the scene being photographed, and the image side is the side of the lens facing the image sensor and imaging plane. These two sides are arranged opposite each other along the optical axis, one on the left and one on the right. The lens optical structure consists of eight independent lenses. After light enters from the external scene, it passes through the first to the eighth lenses in a fixed order. All eight lenses participate in light refraction and imaging. This eight-lens structure is the core foundation for achieving high resolution and small size. The first lens group is used to control the field of view and balance optical lens aberrations, while the second lens group is used to balance optical lens aberrations and chromatic aberration. A positive optical power indicates that the group as a whole has the ability to converge light. The two-stage convergence of light allows for layered correction of various optical aberrations. Combined with the ample aberration correction freedom of the eight lenses, it can stably support high-resolution imaging of 50 million pixels and above, resulting in high image clarity and suitability for high-definition video and high-end video shooting scenarios. The overall axial length from the object-side surface of the first lens to the imaging plane is limited to a maximum of 30mm, which constrains the longitudinal dimension of the lens; D1 is the outer diameter of the first lens, with a maximum of 14mm, which constrains the lateral diameter of the lens; the two dimensional indicators together limit the overall volume of the lens, solving the pain points of existing lenses being too long, having a large diameter, and being difficult to miniaturize equipment.

[0027] For a single lens, the fourth and eighth lenses have positive optical power; the first, second, third, fifth, sixth, and seventh lenses have negative optical power. The first three lenses are all diverging lenses, forming a first lens group with overall positive optical power; individual lenses diverge, while the group as a whole converges. The first lens in the second lens group, the only forward converging lens, receives and converges the diverging beam from the previous group. The three lenses in the middle of the second lens group are all diverging lenses, used to correct various aberrations and smooth the optical path. The converging lens at the end of the optical lens is responsible for precisely focusing the beam onto the image sensor's imaging surface.

[0028] To reduce the axial dimension of the optical lens and improve imaging capabilities, the fourth, fifth, and sixth lenses are cemented together. The adjacent curved surfaces of the three lenses are completely bonded together with optical adhesive, eliminating air gaps between the lenses. This forms an integrated cemented three-lens group, with the positive and negative lenses continuously bonded to simultaneously cancel out monochromatic aberrations such as spherical aberration and coma. The tight bonding of the three lenses significantly compresses the axial space within the second lens group, making it easier to control the overall optical length to within 30mm. Combined with the small-diameter design of the first lens (D1≤14mm), this addresses the drawback of the large size of traditional high-definition lenses, facilitating integration into small communication devices.

[0029] Specifically, the fourth, fifth, and sixth lenses are glass lenses: the refractive index of the fourth lens is N4, and its Abbe number is V4, with 1.45≤N4≤1.5 and 80≤V4≤85; the refractive index of the fifth lens is N5, and its Abbe number is V5, with 1.60≤N5≤1.65 and 40≤V5≤50; the refractive index of the sixth lens is N6, and its Abbe number is V6, with 1.40≤N6≤1.50 and 90≤V6≤96. Unlike plastic aspherical lenses, all three lenses are made of optical glass. Glass has advantages such as high refractive index and Abbe number stability, low temperature drift, high light transmittance, and controllable tolerances, making it suitable for the stringent chromatic aberration correction requirements of high-pixel lenses. Combined with a triple-laminated structure, they form an integrated achromatic core unit.

[0030] The first, third, fourth, fifth, and sixth lenses are all glass spherical lenses, while the second, seventh, and eighth lenses are all plastic aspherical lenses. Glass spherical lenses offer superior surface uniformity and optical stability, ensuring accurate basic imaging and reducing the impact of temperature changes on the optical path. Plastic aspherical lenses, on the other hand, can correct system aberrations through freeform surface design, optimizing field curvature and distortion while reducing the number of lenses used, further compressing the overall lens size. The combination of these two technologies achieves a balance between image quality and miniaturized design.

[0031] In an optical lens, the focal lengths of the lens group and the optical lens must satisfy the following: the focal length of the optical lens is F, the focal length of the first lens group is F1, and the focal length of the second lens group is F2; ​​and satisfy: 1.8≤F1 / F≤2, 3.5≤F2 / F≤4.

[0032] In an optical lens, the focal lengths of a single lens and a lens group must satisfy the following conditions: the focal length of the first lens is f1, -0.8≤f1 / F1≤-0.7; the focal length of the second lens is f2, -4.8≤f2 / F1≤-4.3; the focal length of the third lens is f3, 0.6≤f3 / F1≤0.9; the focal length of the fourth lens is f4, 0.4≤f4 / F2≤0.7; the focal length of the fifth lens is f5, -0.6≤f5 / F2≤-0.3; the focal length of the sixth lens is f6, -1.6≤f6 / F2≤-1.3; the focal length of the seventh lens is f7, 13.5≤f7 / F2≤-12; and the focal length of the eighth lens is f8, 12≤f8 / F2≤22.

[0033] The optical lens also includes an aperture stop and a filter. The aperture stop is positioned between the first lens group and the second lens group. The aperture stop controls the size of the light-gathering aperture. Positioned between the first and second lens groups, the aperture decreases after the light beam passes through the front group. This placement of the aperture stop eliminates the need for a large light-blocking structure, achieving a large aperture and improving brightness in low-light conditions. As the center of optical path symmetry, the two groups of positive and negative lenses symmetrically cancel out spherical aberration, coma, and distortion, making it easier to control lens distortion within 8%. Uniformly constraining the angle of the light beam incident on the rear group, combined with focal length ratio constraints, stably controls the principal ray incident angle (CRA) within ±2.5°, avoiding vignetting at the sensor edges. The filter is positioned on the image side of the eighth lens. It filters infrared stray light to prevent color distortion.

[0034] The aperture value of the optical lens is greater than or equal to 2.0 and less than or equal to 2.4; the aperture size of the stop is D2, 6mm≤D2≤7mm; the large aperture combined with the large light-gathering aperture ensures sufficient light intake, eliminating the need to increase the sensor gain in low-light environments, resulting in less image noise and complete detail retention, making it suitable for indoor video calls and nighttime security communication camera scenarios.

[0035] The distance between the first and second lenses is L1, 3mm ≤ L1 ≤ 3.5mm; L1 appropriately separates the first two negative lenses, smoothing the wide-angle light in layers, suppressing edge distortion and astigmatism, easily achieving distortion ≤ 8%; the distance between the third and fourth lenses is L2, 2mm ≤ L2 ≤ 2.5mm. L2 provides reasonable installation space for the aperture stop, placing it in the optimal symmetrical position of the optical path, with the front and rear lens groups symmetrically canceling spherical aberration and coma. The angle between the principal ray of the optical lens and the image plane is CRA, -2.5° ≤ CRA ≤ 2.5°; and the lens optical distortion is less than 8%. Suitable for video conferencing cameras, smart terminals, security communication cameras, and other equipment, the high-definition, distortion-free, and vignetting-free imaging effect meets the needs of high-definition video and intelligent recognition (face recognition, object detection), with higher edge target recognition accuracy.

[0036] In one specific embodiment of the optical lens: Table 1 shows the specific parameters of each lens:

[0037] Table 2: Conicity and Asphericity of Aspherical Lenses The surface profile of an aspherical lens satisfies the formula:

[0038] Where z represents the axial sagitta in the Z direction of the aspherical surface; y represents the height of the aspherical surface; c represents the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k represents the conic coefficient; and the 4th, 6th, 8th, 10th, and 12th order terms represent higher-order aspherical coefficients, respectively.

[0039]

[0040]

[0041] The present invention also proposes a communication device, which includes an optical lens. The specific structure of the optical lens is as described in the above embodiments. Since the communication device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0042] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An optical lens, characterized in that, The optical lens has an object side and an image side that are arranged opposite to each other along the optical axis. The optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side to the image side. The first lens, the second lens, and the third lens together form a first lens group, and the optical power of the first lens group is positive; the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens together form a second lens group, and the optical power of the second lens group is positive. The total optical length of the optical lens is TTL, TTL≤30mm, and the diameter of the first lens is D1, which satisfies: D1≤14mm; the imaging quality of the optical lens is greater than or equal to 50 million pixels.

2. The optical lens as described in claim 1, characterized in that, The optical power of the fourth lens and the eighth lens is positive. The first lens, the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens have negative optical power.

3. The optical lens as described in claim 1, characterized in that, The fourth lens, the fifth lens, and the sixth lens are cemented together.

4. The optical lens as described in claim 1, characterized in that, The fourth lens, the fifth lens, and the sixth lens are glass lenses. The refractive index of the fourth lens is N4, and the Abbe number of the fourth lens is V4, where 1.45≤N4≤1.5 and 80≤V4≤85. The refractive index of the fifth lens is N5, and the Abbe number of the fourth lens is V5, where 1.60≤N5≤1.65 and 40≤V5≤50. The refractive index of the sixth lens is N6, and the Abbe number of the fourth lens is V6, where 1.40≤N6≤1.50 and 90≤V6≤96.

5. The optical lens as described in claim 1, characterized in that, The focal length of the optical lens is F, the focal length of the first lens group is F1, and the focal length of the second lens group is F2. It satisfies: 1.8≤F1 / F≤2, 3.5≤F2 / F≤4.

6. The optical lens as described in claim 5, characterized in that, The focal length of the first lens is f1, and -0.8 ≤ f1 / F1 ≤ -0.7; The focal length of the second lens is f2, -4.8≤f2 / F1≤-4.3; The focal length of the third lens is f3, and 0.6 ≤ f3 / F1 ≤ 0.9; The focal length of the fourth lens is f4, and 0.4 ≤ f4 / F2 ≤ 0.7; The focal length of the fifth lens is f5, and -0.6 ≤ f5 / F2 ≤ -0.3; The focal length of the sixth lens is f6, and -1.6 ≤ f6 / F2 ≤ -1.3; The focal length of the seventh lens is f7, and 13.5≤f7 / F2≤-12; The focal length of the eighth lens is f8, and 12≤f8 / F2≤22.

7. The optical lens as described in claim 1, characterized in that, The optical lens also includes: An aperture stop is positioned between the first lens group and the second lens group; A filter is disposed on the image side of the eighth lens.

8. The optical lens as described in claim 7, characterized in that, The aperture value of the optical lens is greater than or equal to 2.0 and less than or equal to 2.4; and / or, The aperture size of the aperture stop is D2, 6mm≤D2≤7mm; and / or, The distance between the first lens and the second lens is L1, where 3mm ≤ L1 ≤ 3.5mm; the distance between the third lens and the fourth lens is L2, where 2mm ≤ L2 ≤ 2.5mm.

9. The optical lens as described in claim 1, characterized in that, The angle between the principal ray of the optical lens and the image plane is CRA, -2.5°≤CRA≤2.5°; and / or, The optical distortion of the optical lens is less than 8%.

10. A communication device, characterized in that, Includes the optical lens as described in any one of claims 1 to 9.

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