Low-distortion and large-target-surface video conference lens and electronic equipment

Abstract

The invention discloses a low-distortion and large-target-surface video conference lens and electronic equipment. The lens sequentially comprises 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 from the object side to the image side. The first lens has negative diopter, the object side surface of the lens is a convex surface, and the image side surface of the lens is a concave surface; the second lens has positive diopter, the object side surface of the lens is a convex surface, and the image side surface of the lens is a concave surface. The invention provides an innovative optical design for solving the problem that the existing video conference lens cannot give consideration to the problems of small size, large target surface, large CRA, high definition, low distortion and small field curvature. Through the glass-plastic mixed design, the use number of glass lenses is reduced, and the video conference lens with small volume, large target surface, large CRA, high definition, low distortion and small field curvature is realized by matching with a sensor with a 1 / 1.56 inch target surface.

Description

Technical Field

[0001] The present invention relates to the technical field of video conferencing lenses, and particularly to a low-distortion, large-image-plane video conferencing lens and an electronic device. Background Art

[0002] With the rapid development of the network, the convenience of online meetings, online education, live streaming and other online work has become increasingly prominent. It has the advantages of instant multi-party communication that breaks through time and space limitations, accelerating the decision-making process, and adapting to various scenarios for hybrid work. As the "eyes" of online work, video conferencing lenses can collect and image to meet the virtual reality communication during the meeting, and their performance directly affects the clarity, smoothness and stability of video services. With the continuous improvement of the technical index requirements of video conferencing systems, while requiring the lens to have a larger image plane, smaller distortion and field curvature, higher requirements are put forward for the small volume and imaging quality of the lens.

[0003] At present, existing video conferencing lenses still cannot balance high image quality, large image plane and small volume, and cannot meet the application requirements of some scenarios, such as the problem that the field of view corresponding CRA cannot match the non-linear CRA curve of high-end sensors, and the field curvature of the lens is not small enough. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a low-distortion, large-image-plane video conferencing lens and an electronic device. This lens can at least solve one of the technical drawbacks mentioned in the background art.

[0005] According to one aspect of the present invention, there is provided a low-distortion, large-image-plane video conferencing lens, which sequentially 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 from the object side to the image side;

[0006] The first lens has a negative refractive power, the object side surface of the lens is convex, and the image side surface of the lens is concave;

[0007] The second lens has a positive refractive power, the object side surface of the lens is convex, and the image side surface of the lens is concave;

[0008] The third lens has a negative refractive power, the object side surface of the lens is convex, and the image side surface of the lens is concave;

[0009] The fourth lens has a positive refractive power, the object side surface of the lens is convex, and the image side surface of the lens is concave;

[0010] The fifth lens has a positive refractive power, the object side surface of the lens is convex, and the image side surface of the lens is convex;

[0011] The sixth lens has a negative refractive power, the object side surface of the lens is concave, and the image side surface of the lens is concave;

[0012] The seventh lens has a positive refractive power. The object side of the lens is concave, and the image side of the lens is convex;

[0013] The eighth lens has a negative refractive power. The object side of the lens is concave, and the image side of the lens is concave;

[0014] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are glass lenses; the seventh lens, the eighth lens, and the ninth lens are plastic lenses.

[0015] In the above technical solution, the present invention addresses the problem that existing video conferencing lenses cannot simultaneously achieve small size, large target surface, large CRA, high definition, low distortion, and small field curvature, and proposes an innovative optical design. Through a hybrid glass and plastic design, the number of glass lenses used is reduced, and at the same time, a sensor with a 1 / 1.56-inch target surface is used to achieve a video conferencing lens with small size, large target surface, large CRA, high definition, low distortion, and small field curvature, significantly improving the imaging quality. Specifically:

[0016] (1) Through the combination of lenses with different refractive powers, by compressing the field of view angle and expanding the light beam, the light is gently deflected towards the optical axis direction, reducing the tolerance sensitivity. At the same time, the outer diameter size of the subsequent lenses is effectively reduced, taking into account the characteristics of a large field of view angle and small size, effectively shortening the overall length of the lens, reducing the lens cost, and maintaining the large image surface and high image quality performance of the system;

[0017] (2) By using a structure of four lenses in the front group and four lenses in the rear group to improve the image quality and reduce the system distortion, the combination of glass spherical lenses and plastic aspherical lenses takes into account the large image surface and small size, and effectively reduces the number of lenses and the outer diameter size.

[0018] (3) By comprehensively considering the hybrid glass and plastic design, optimized optical path, and target surface adaptability, the present invention reduces the lens cost, shortens the overall length of the lens, and reduces the lens weight while ensuring good imaging quality of the system, providing technical support for the miniaturization and high performance of video conferencing lenses.

[0019] In some embodiments, a diaphragm is provided between the fourth lens and the fifth lens, and the seventh lens is a plastic aspherical lens made of a high refractive index material.

[0020] In the above technical solution, the present invention further improves the performance of the video conferencing lens by optimizing the structural design of the optical system. Specifically, a diaphragm is provided between the fourth lens and the fifth lens, and the seventh lens is a plastic aspherical lens made of a high refractive index material.

[0021] (1) The diaphragm is disposed between the fourth lens and the fifth lens. This design can effectively control the incident angle and path of light, optimize the light distribution in the optical system. By adjusting the distance between the lens and the diaphragm, astigmatism can be corrected, and it performs excellently especially in correcting coma, distortion, and lateral chromatic aberration. This selection of the diaphragm position not only improves the imaging quality but also provides a greater optimization space for the design of subsequent lenses.

[0022] (2) The seventh lens is a plastic aspherical lens made of a high-refractive-index material. The high-refractive-index material can effectively correct the spherical aberration and coma of the optical system. Especially under the conditions of a large field of view angle and a large aperture, it can significantly improve the clarity and consistency of imaging. The design of the aspherical lens can achieve complex light correction functions within a smaller lens size, thereby reducing the lens spacing and effectively shortening the total length of the optical system. The combination of the high-refractive-index material and the aspherical design can, while ensuring the imaging quality, further reduce the tolerance sensitivity of the system, improve the production consistency and reliability.

[0023] (3) Through the optimization of the diaphragm position and the application of high-refractive-index material glass aspherical lenses, the lens spacing is reduced and the light path is optimized, significantly reducing the overall size of the lens, meeting the development requirements of miniaturization and lightweight of the video conferencing lens. It effectively corrects spherical aberration, coma, astigmatism, distortion, and lateral chromatic aberration, ensuring the high resolution and large target surface compatibility of the imaging system. The combined design of the high-refractive-index material and the aspherical lens reduces the dependence on complex lens groups, while improving the production efficiency and the yield rate.

[0024] In some embodiments, the lens satisfies the following conditional expressions:

[0025] 1.63 < nd1 < 1.80, 45 < vd1 < 62;

[0026] 1.80 < nd2 < 1.95, 16 < vd2 < 40;

[0027] 1.75 < nd3 < 1.85, 23 < vd3 < 30;

[0028] 1.58 < nd4 < 1.75, 50 < vd4 < 70;

[0029] 1.50 < nd5 < 1.55, 55 < vd5 < 58;

[0030] 1.63 < nd6 < 1.67, 19 < vd6 < 24;

[0031] 1.98 < nd7 < 2.12, 16 < vd7 < 29;

[0032] 1.65 < nd8 < 1.68, 19 < vd8 < 21;

[0033] In the formula, nd1 to nd9 are the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively, and vd1 to vd9 are the dispersion coefficients of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively.

[0034] In the above technical solution, the reasonable combination of the refractive index and dispersion coefficient of each lens ensures that the optical system achieves high-resolution and high-contrast imaging effects within the full field of view, meeting the requirements of high-definition imaging power. By optimizing the lens material and structure design, the number and size of the lenses are reduced, effectively shortening the total length of the optical system, while reducing the weight of the lens, meeting the development trend of miniaturization and light weight of video conferencing lenses. The reasonable combination of high Abbe number and low Abbe number materials reduces the dependence on expensive optical materials, while improving production efficiency and yield rate, and reducing the overall production cost.

[0035] In some embodiments, the third lens and the fourth lens are designed as doublet lenses, and the image side of the fourth lens is concave.

[0036] In the above technical solution, the doublet lens can effectively correct axial chromatic aberration and lateral chromatic aberration by reasonably combining materials with different refractive indices and dispersion coefficients, ensuring color consistency and clarity of imaging. The design of the doublet lens can optimize the light convergence path, reduce spherical aberration and astigmatism, and improve imaging uniformity and contrast. The cemented design reduces the air gap between the lenses, reduces the reflection and scattering of light at the interface, and improves the stability and reliability of the system. In addition, the fourth lens and the fifth lens are set to have positive optical power. The positive optical power design helps the convergence of light, ensuring that the incident light beams in each field of view can be accurately deflected and converged on the imaging surface after passing through the optical system, improving imaging clarity and resolution. The positive optical power lens can effectively suppress aberration phenomena such as spherical aberration, chromatic aberration, field curvature, and astigmatism, ensuring that the optical system achieves high-resolution and high-contrast imaging effects within the full field of view. The synergistic effect of the doublet lens and the positive optical power lens ensures that the optical system achieves high-resolution and high-contrast imaging effects within the full field of view, meeting the requirements of high-definition imaging power. By optimizing the lens combination and structure design, the total number and size of the lenses are reduced, effectively shortening the total length of the optical system, while reducing the weight of the lens, meeting the development needs of miniaturization and light weight of video conferencing lenses.

[0037] In summary, the present invention designs the third lens and the fourth lens as doublet lenses, and sets the fourth lens and the fifth lens to have positive optical power, solving the technical problems of chromatic aberration correction, imaging quality optimization, and miniaturization in existing video conferencing lenses, and having significant innovation and practicality.

[0038] In some embodiments, the lens satisfies the following conditional formula:

[0039] nd7 > 1.98

[0040] wherein, nd7 is the refractive index of the seventh lens.

[0041] In the above technical solution, the high-refractive-index material can effectively correct the spherical aberration, coma, and chromatic aberration of the optical system. Especially under the conditions of a large aperture and a large field of view angle, it can significantly improve the imaging clarity and consistency. The high-refractive-index material allows the lens to be designed thinner, and at the same time, it can achieve complex light correction functions within a smaller lens spacing, thereby effectively shortening the total length of the optical system and meeting the development requirements of the miniaturization of the drone lens. Combining with the design that the aperture stop is arranged between the fifth lens and the sixth lens, the application of the high-refractive-index material further enhances the performance of the optical system.

[0042] In some embodiments, the lens satisfies the following conditional formula:

[0043] nd6 < nd8 < nd7; vd7 < vd6

[0044] wherein, nd6, nd7, and nd8 are the refractive indices of the sixth lens, the seventh lens, and the eighth lens respectively, and vd6 and vd7 are the dispersion coefficients of the sixth lens and the seventh lens.

[0045] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, and the seventh lens are glass spherical lenses, and the fifth lens, the sixth lens, and the eighth lens are plastic aspherical lenses.

[0046] In the above technical solution, by using aspherical lenses for the rear group of the fifth lens, the sixth lens, and the eighth lens, and by increasing the order of the even aspherical surfaces, the utilization efficiency of each lens is improved, thereby reducing the number of lenses used, effectively reducing the volume of the lens, and also effectively controlling the peripheral distortion. At the same time, through the special shape of the last plastic aspherical lens, a non-linear relationship between the image height and the CRA is realized to match the CRA curve of the high-end Sensor.

[0047] By using aspherical lenses in the fifth lens, the sixth lens, and the eighth lens, the present invention can significantly improve the performance of the optical system. Aspherical lenses can effectively correct aberration phenomena such as spherical aberration, coma, astigmatism, and distortion. Especially under the conditions of a large field of view angle and a large aperture, the clarity and consistency of imaging are significantly improved. The application of aspherical lenses effectively corrects various aberrations, ensuring that the optical system achieves high-resolution and high-contrast imaging effects within the entire field of view and meets the requirements of high-definition imaging. By increasing the order of even aspheres, each aspherical lens can undertake more optical functions, thereby reducing the number of lenses used and making the optical system more compact, meeting the development trend of miniaturization and lightweight of video conferencing lenses. Aspherical lenses can effectively control the deflection of light in the edge region, reduce edge distortion, and improve the uniformity and overall quality of imaging. Glass lenses have the characteristics of high refractive index and low dispersion, which are suitable for correcting chromatic aberration and improving imaging quality; plastic lenses have the advantages of lightweight and low cost, and are suitable for aspherical design to further optimize aberration correction. The combined design of glass and plastic lenses reduces the total number and size of lenses, effectively shortens the total length of the optical system, and at the same time reduces the weight of the lens. The use of plastic aspherical lenses reduces the dependence on expensive glass materials, improves production efficiency and yield rate, and reduces the overall production cost.

[0048] In some embodiments, the lens satisfies the following conditional formula:

[0049] 3 < TTL / f < 4;

[0050] In the formula, TTL is the total optical length of the lens, and f is the focal length of the lens.

[0051] In the above technical solution, by reasonably controlling the ratio of the total optical length (TTL) to the focal length (f), the best balance between the volume and imaging quality of the optical system is ensured. Specifically: when the ratio of the total optical length to the focal length satisfies 3 < TTL / f < 4, the optical system can ensure excellent imaging quality while maintaining a small volume. This design precisely controls the compactness of the optical system, avoiding the degradation of imaging quality caused by too small a volume and the unsatisfactory miniaturization caused by too large a volume. When TTL / F < 3, the volume of the optical system is likely to be too small and the imaging quality is reduced; when 3 < TTL / F < 4, the volume of the optical system can be controlled, taking into account both small volume and imaging quality; when TTL / F > 4, the possibility of the optical lens being too large increases, the miniaturization of the lens is unsatisfactory, the manufacturing cost and portability problems increase, and at the same time, it may lead to redundancy of optical performance.

[0052] The TTL of the video conferencing lens of this application is < 25mm, the effective diameter of the lens is < φ18.3mm, F < 6.3mm, and it has a small volume; the MTF is greater than 0.3 in the entire field of view at a frequency of 250 lp / mm, and the imaging quality is good; the target surface height > 10.3mm, which can match a 1 / 1.56” sensor, with a large target surface; the lateral chromatic aberration is within the radius of the Airy disk, and the axial chromatic aberration of each wavelength is small, and the imaging picture will not be affected by blue-violet edges; the F-Tan(Theta) distortion < 5%, and the TV distortion < 4%. The imaging picture of this system will not affect the visual perception due to distortion.

[0053] In some embodiments,

[0054] According to another aspect of the present invention, there is provided an electronic device, including a low-distortion, large-target video conferencing lens as described above; and an image sensor configured to receive the image formed by the low-distortion, large-target video conferencing lens.

[0055] In the above technical solution, the advantages of this electronic device rely on the low-distortion, large-target video conferencing lens, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0057] Figure 1 It is a schematic structural diagram of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0058] Figure 2 It is an MTF curve graph of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0059] Figure 3 It is a Through Focus curve graph of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0060] Figure 4 It is a lateral chromatic aberration curve graph of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0061] Figure 5 It is an axial chromatic aberration curve graph of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0062] Figure 6 It is a field curvature & distortion curve graph of Example 1 of the low-distortion, large-target video conferencing lens of the present invention;

[0063] Figure 7 Schematic diagram of the structure of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0064] Figure 8 MTF curve graph of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0065] Figure 9 Through Focus curve graph of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0066] Figure 10 Lateral chromatic aberration curve graph of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0067] Figure 11 Longitudinal chromatic aberration curve graph of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0068] Figure 12 Field curvature & distortion curve graph of Example 2 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0069] Figure 13 Schematic diagram of the structure of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0070] Figure 14 MTF curve graph of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0071] Figure 15 Through Focus curve graph of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0072] Figure 16 Lateral chromatic aberration curve graph of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0073] Figure 17 Longitudinal chromatic aberration curve graph of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0074] Figure 18 Field curvature & distortion curve graph of Example 3 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0075] Figure 19 Schematic diagram of the structure of Example 4 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0076] Figure 20 MTF curve graph of Example 4 of the low-distortion and large-image-plane video conferencing lens of the present invention;

[0077] Figure 21Example 4 Through Focus curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0078] Figure 22 Example 4 lateral chromatic aberration curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0079] Figure 23 Example 4 axial chromatic aberration curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0080] Figure 24 Example 4 field curvature & distortion curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0081] Figure 25 Structure schematic diagram of Example 5 of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0082] Figure 26 Example 5 MTF curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0083] Figure 27 Example 5 Through Focus curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0084] Figure 28 Example 5 lateral chromatic aberration curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0085] Figure 29 Example 5 axial chromatic aberration curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0086] Figure 30 Example 5 field curvature & distortion curve graph of the low-distortion and large-image-circle video conferencing lens of the present invention;

[0087] Figure 31 Structure schematic diagram of Example 6 of the electronic device of the present invention. Detailed implementation manners

[0088] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be specifically pointed out that the following embodiments are only used to illustrate the present invention, but do not limit the scope of the present invention. Similarly, the following embodiments are only partial embodiments of the present invention rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0089] The object of the present invention is to provide a low-distortion and large-image-circle video conferencing lens and an electronic device with high optical performance. Embodiments according to the present invention will now be described in detail with reference to the accompanying drawings.

[0090] Figure 1 , Figure 7 , Figure 13 , Figure 19 , Figure 25 are respectively cross-sectional views of low-distortion, large-image-plane video conferencing lenses (optical systems) according to Examples 1 to 5. The low-distortion, large-image-plane video conferencing lenses according to each example are used for a video conferencing camera including an interchangeable lens or a video conferencing camera with a non-interchangeable lens. In each cross-sectional view, the left side is the object side OBJ and the right side is the image side IMA. In each cross-sectional view, Li represents the i-th lens, ST represents the aperture (fixed aperture or visible aperture), and G1 represents the protective glass & filter. IMA represents the image plane, and when the low-distortion, large-image-plane video conferencing lenses 1 to 5 according to each example are used for a video conferencing camera including an interchangeable lens or a video conferencing camera with a non-interchangeable lens, a solid-state imaging element (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor is arranged on the imaging plane IMA.

[0091] For the low-distortion, large-image-plane video conferencing lens according to each example, the first lens 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, and the eighth lens L8 are arranged in sequence from the object side to the image side;

[0092] The first lens L1 has a negative refractive power, the object side surface of the lens is convex, and the image side surface is concave;

[0093] The second lens L2 has a positive refractive power, the object side surface of the lens is convex, and the image side surface is concave;

[0094] The third lens L3 has a negative refractive power, the object side surface of the lens is convex, and the image side surface is concave;

[0095] The fourth lens L4 has a positive refractive power, the object side surface of the lens is convex, and the image side surface is concave;

[0096] The fifth lens L5 has a positive refractive power, the object side surface of the lens is convex, and the image side surface is convex;

[0097] The sixth lens L6 has a negative refractive power, the object side surface of the lens is concave, and the image side surface is concave;

[0098] The seventh lens L7 has a positive refractive power, the object side surface of the lens is concave, and the image side surface is convex;

[0099] The eighth lens L8 has a negative refractive power, the object side surface of the lens is concave, and the image side surface of the lens is concave; the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the seventh lens L7 are glass spherical lenses, and the fifth lens L5, the sixth lens L6, and the eighth lens L8 are plastic aspherical lenses.

[0100] The third lens L3 and the fourth lens L4 are designed as doublet lenses, and at the same time, the image side surface of the fourth lens L4 is set as a concave surface.

[0101] The low-distortion, large-target video conferencing lens according to each example can satisfy at least one of the following setting conditions 1) to 4):

[0102] 1) 1.63 < nd1 < 1.80, 45 < vd1 < 62; 1.80 < nd2 < 1.95, 16 < vd2 < 40; 1.75 < nd3 < 1.85, 23 < vd3 < 30; 1.58 < nd4 < 1.75, 50 < vd4 < 70; 1.50 < nd5 < 1.55, 55 < vd5 < 58; 1.63 < nd6 < 1.67, 19 < vd6 < 24; 1.98 < nd7 < 2.12, 16 < vd7 < 29;

[0103] 1.65 < nd8 < 1.68, 19 < vd8 < 21;

[0104] 2) nd7 > 1.98;

[0105] 3) nd6 < nd8 < nd7; vd7 < vd6;

[0106] 4) 3 < TTL / f < 4.

[0107] In the above conditional expressions, f is the focal length of the lens; nd1 to nd9 are the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively, and vd1 to vd9 are the dispersion coefficients of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively; TTL is the total optical system length of the lens.

[0108] Now, a detailed description of the low-distortion, large-target video conferencing lens according to each example will be given.

[0109] For the optical structure of Example 1, please refer to Figure 1 , and the specific parameters of this Example 1 are shown in Table 1 and Table 2 below. In this Example 1, the lens focal length f' = 6.23 mm, the effective diameter of the first lens is 17.003 mm, and the target surface height is 10.350 mm.

[0110] Table 1 Parameter Table of Example 1

[0111]

[0112] Table 2 Aspherical Parameter Table of Example 1

[0113]

[0114]

[0115] Figure 2 It is the MTF curve graph of Example 1. The MTF of the full field of view is greater than 0.3 at 250 lp / mm and greater than 0.6 at 125 lp / mm. Figure 3 It is the Through Focus curve graph of Example 1. The curves of the full field of view are concentrated with small defocus amounts. The field curvature of each field of view is less than 3 um and the astigmatism is small. Figure 4 It is the lateral chromatic aberration curve graph of Example 1. The correction of the lateral chromatic aberration of the lens is less than 1.7 um. Figure 5 It is the axial chromatic aberration curve graph of Example 1. The axial chromatic aberration from 435 nm to 650 nm is small and the blue-violet edge phenomenon is small. Figure 6 It is the field curvature & distortion curve graph of Example 1. The field curvature curves of each wavelength coincide, and the chromatic aberration correction of the lens is good; the distortion is <5%, the TV distortion is <4%, and the imaging picture will not be affected by the distortion in terms of visual perception.

[0116] For the optical structure of Example 2, please refer to Figure 7 , and the specific parameters of this Example 2 are shown in Table 3 and Table 4 below. In this Example 2, the focal length f' = 6.24 mm, the effective diameter of the first lens is 16.969 mm, and the target surface height is 10.321 mm.

[0117] Table 3 Parameter Table of Example 2

[0118]

[0119]

[0120] Table 4 Aspherical Parameter Table of Example 2

[0121]

[0122] Figure 8 It is the MTF curve graph of Example 2. The MTF of the full field of view is greater than 0.3 at 250 lp / mm and greater than 0.6 at 125 lp / mm. Figure 9 It is the Through Focus curve graph of Example 2. The curves of the full field of view are concentrated with small defocus amounts. The field curvature of each field of view is less than 3 um and the astigmatism is small. Figure 10 It is the lateral chromatic aberration curve graph of Example 2. The correction of the lateral chromatic aberration of the lens is less than 1.7 um. Figure 11 It is the axial chromatic aberration curve graph of Example 2. The axial chromatic aberration from 435 nm to 650 nm is small and the blue-violet edge phenomenon is small. Figure 12 It is the field curvature & distortion curve graph of Example 2. The field curvature curves of each wavelength coincide, and the chromatic aberration correction of the lens is good; the distortion is <5%, the TV distortion is <4%, and the imaging picture will not be affected by the distortion in terms of visual perception.

[0123] For the optical structure of Example 3, please refer toFigure 13 For Example 3, the specific parameters are shown in Tables 5 and 6 below. In this Example 3, the focal length of the lens f' = 6.24 mm, the effective diameter of the first lens is 16.031 mm, and the target surface height is 10.330 mm.

[0124] Table 5 Parameter Table of Example 3

[0125]

[0126]

[0127] Table 6 Aspherical Parameter Table of Example 3

[0128]

[0129] Figure 14 The MTF curve of Example 3 shows that the MTF of the full field of view is greater than 0.3 at 250 lp / mm and greater than 0.6 at 125 lp / mm. Figure 15 The Through Focus curve of Example 3 shows that the curves of the full field of view are concentrated with small defocus amounts, the field curvature of each field of view is less than 3 um and the astigmatism is small. Figure 16 The lateral chromatic aberration curve of Example 3 shows that the lateral chromatic aberration correction of the lens is less than 1.7 um. Figure 17 The axial chromatic aberration curve of Example 3 shows that the axial chromatic aberration from 435 nm to 650 nm is small and the blue-violet edge phenomenon is small. Figure 18 The field curvature & distortion curve of Example 3 shows that the field curvature curves of each wavelength coincide, and the chromatic aberration correction of the lens is good; the distortion < 5%, the TV distortion < 4%, and the imaging picture will not be affected by the distortion in terms of visual perception.

[0130] For the optical structure of Example 4, please refer to Figure 19 For Example 4, the specific parameters are shown in Tables 7 and 8 below. In this Example 4, the focal length of the lens f' = 6.24 mm, the effective diameter of the first lens is 18.268 mm, and the target surface height is 10.369 mm.

[0131] Table 7 Parameter Table of Example 4

[0132]

[0133]

[0134] Table 8 Aspherical Parameter Table of Example 4

[0135]

[0136] Figure 20 The MTF curve of Example 3 shows that the MTF of the full field of view is greater than 0.3 at 250 lp / mm and greater than 0.6 at 125 lp / mm. Figure 21For the Through Focus curve graph of Example 3, the full field of view curves are concentrated with small defocus amounts, the field curvatures of each field of view are all less than 3um and the astigmatism is small. Figure 22 For the lateral chromatic aberration curve graph of Example 3, the lateral chromatic aberration correction of the lens is less than 1.7um. Figure 23 For the axial chromatic aberration curve graph of Example 3, the axial chromatic aberration from 435nm to 650nm is small and the blue-violet edge phenomenon is small. Figure 24 For the field curvature & distortion curve graph of Example 3, the field curvature curves of each wavelength coincide, and the chromatic aberration correction of the lens is good; the distortion < 5%, the TV distortion < 4%, and the imaging picture will not be affected by the distortion in terms of visual perception.

[0137] Please refer to the optical structure of Example 5 Figure 25 , and the specific parameters of this Example 5 are shown in Table 9 and Table 10 below. In this Example 5, the lens focal length f' = 6.24mm, the effective diameter of the first lens is 18.047mm, and the target surface height is 10.351mm.

[0138] Table 9 Parameter Table of Example 5

[0139]

[0140]

[0141] Table 10 Aspherical Parameter Table of Example 5

[0142]

[0143] Figure 26 For the MTF curve graph of Example 5, the full field of view MTF is greater than 0.3 at 250lp / mm and greater than 0.6 at 125lp / mm. Figure 27 For the Through Focus curve graph of Example 5, the full field of view curves are concentrated with small defocus amounts, the field curvatures of each field of view are all less than 3um and the astigmatism is small. Figure 28 For the lateral chromatic aberration curve graph of Example 5, the lateral chromatic aberration correction of the lens is less than 1.7um. Figure 29 For the axial chromatic aberration curve graph of Example 5, the axial chromatic aberration from 435nm to 650nm is small and the blue-violet edge phenomenon is small. Figure 30 For the field curvature & distortion curve graph of Example 5, the field curvature curves of each wavelength coincide, and the chromatic aberration correction of the lens is good; the distortion < 5%, the TV distortion < 4%, and the imaging picture will not be affected by the distortion in terms of visual perception.

[0144] Based on Examples 1 to 5, the present case has the following specific advantages: Optimization of the effective diameter of the lens and the system size By restricting the effective diameter of the lens to be less than φ18.3mm, the present invention significantly reduces the physical size of the lens while ensuring the performance of the optical system. This design makes the lens more compact, meeting the requirements of videoconferencing for miniaturization and lightweight. The focal length F is less than 6.3mm, achieving large-angle imaging, capable of covering a wider area, and is particularly suitable for videoconferencing applications. The lens adopts a hybrid glass and plastic design, reducing the number of glass lenses used. At the same time, by utilizing the lightweight characteristics of plastic lenses, the weight of the lens is significantly reduced, improving the battery life and mobility of videoconferencing. MTF performance: At a frequency of 250lp / mm, the modulation transfer function (MTF) values across the entire field of view are all greater than 0.3, ensuring high imaging resolution and image clarity. Target surface height matching: The target surface height is greater than 10.3mm, capable of matching a large target surface sensor of 1 / 1.51 inches, ensuring that the imaging surface covers the entire sensor and improving the integrity and quality of imaging. Through the above design, the present invention has achieved significant technological progress in the following aspects:

[0145] Improved imaging quality: The high-resolution, large field of view angle, and large aperture design ensure high imaging quality of the optical system in various environments, meeting the requirements of high-definition imaging capabilities.

[0146] System miniaturization and lightweight: By optimizing the lens material and structural design, the number and size of the lenses are reduced, effectively shortening the total length of the optical system. At the same time, the weight of the lens is reduced, meeting the development trend of miniaturization and lightweight of videoconference lenses.

[0147] Reduced production cost: The hybrid glass and plastic design and the reasonable combination of high Abbe number and low Abbe number materials reduce the dependence on expensive optical materials. At the same time, the production efficiency and the yield rate are improved, reducing the overall production cost.

[0148] Color reproduction and uniformity: By optimizing the light path and correcting aberrations, the color consistency and uniformity of imaging are ensured, improving the visual effect of the image.

[0149] In summary, by precisely defining the refractive index and dispersion coefficient of each lens, combining aspherical design and material optimization, the present invention solves the technical problems of chromatic aberration correction, imaging quality optimization, and miniaturization in existing videoconference lenses, and has significant innovation and practicality.

[0150] Example 6

[0151] Now referring to Figure 31 , a description of the electronic device A according to Example 6 of the present invention will be given. Figure 31It is a schematic diagram of an electronic device (video conferencing camera) that uses any one of the low-distortion, large-target video conferencing lenses according to Examples 1 to 5 for a camera optical system.

[0152] In Figure 31 it, reference numeral A2 denotes the electronic device body, and reference numeral A1 denotes an imaging optical system (interchangeable lens) including any one of the low-distortion, large-target video conferencing lenses according to Examples 1 to 6. Reference numeral A3 denotes an image sensor (photoelectric conversion element) such as a CMOS image sensor or a CCD image sensor, which is built in the camera body A2 and receives light (optical image formed by the imaging optical system 11) from the imaging optical system A1 and performs photoelectric conversion.

[0153] By using a low-distortion, large-target video conferencing lens according to any one of Examples 1 to 6 for an electronic device such as a digital still camera, an electronic device with high optical performance can be obtained.

[0154] Each example can provide an electronic device with high optical performance.

[0155] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the 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. A video conferencing lens with low distortion and a large target surface, characterized in that, From the object side to the image side, there are, in sequence, 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; The first lens has a negative refractive power. The object side surface of this lens is convex, and the image side surface of this lens is concave; The second lens has a positive refractive power. The object side surface of this lens is convex, and the image side surface of this lens is concave; The third lens has a negative refractive power. The object side surface of this lens is convex, and the image side surface of this lens is concave; The fourth lens has a positive refractive power. The object side surface of this lens is convex, and the image side surface of this lens is concave; The fifth lens has a positive refractive power. The object side surface of this lens is convex, and the image side surface of this lens is convex; The sixth lens has a negative refractive power. The object side surface of this lens is concave, and the image side surface of this lens is concave; The seventh lens has a positive refractive power. The object side surface of this lens is concave, and the image side surface of this lens is convex; The eighth lens has a negative refractive power. The object side surface of this lens is concave, and the image side surface of this lens is concave; The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are glass lenses; the seventh lens, the eighth lens, and the ninth lens are plastic lenses.

2. A low-distortion, large-target-surface video conferencing lens according to claim 1, wherein, a diaphragm is provided between the fourth lens and the fifth lens, and the seventh lens is a plastic aspherical lens made of a high refractive index material.

3. A low-distortion, large-target-surface video conferencing lens according to claim 1, wherein, the lens satisfies the following conditional expressions: 1.63 < nd1 < 1.80, 45 < vd1 < 62; 1.80 < nd2 < 1.95, 16 < vd2 < 40; 1.75 < nd3 < 1.85, 23 < vd3 < 30; 1.58 < nd4 < 1.75, 50 < vd4 < 70; 1.50 < nd5 < 1.55, 55 < vd5 < 58; 1.63 < nd6 < 1.67, 19 < vd6 < 24; 1.98 < nd7 < 2.12, 16 < vd7 < 29; 1.65 < nd8 < 1.68, 19 < vd8 < 21; In the formulas, nd1 to nd9 are the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively, and vd1 to vd9 are the dispersion coefficients of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens respectively.

4. A low-distortion, large-target-surface video conferencing lens according to claim 1, wherein, the third lens and the fourth lens are designed as doublet lenses, and at the same time, the image side surface of the fourth lens is concave.

5. A low-distortion, large-target-surface video conferencing lens according to claim 1, wherein, the lens satisfies the following conditional expression: nd7 > 1.98 In the formula, nd7 is the refractive index of the seventh lens.

6. A low-distortion, large-target-surface video conferencing lens according to claim 1 or 3, wherein, the lens satisfies the following conditional expressions: nd6 < nd8 < nd7; vd7 < vd6 Wherein, nd6, nd7, and nd8 are the refractive indices of the sixth lens, the seventh lens, and the eighth lens, and vd6 and vd7 are the dispersion coefficients of the sixth lens and the seventh lens.

7. A low-distortion, large-target video conferencing lens according to claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, and the seventh lens are glass spherical lenses, and the fifth lens, the sixth lens, and the eighth lens are plastic aspherical lenses.

8. A low-distortion, large-target video conferencing lens according to claim 1, wherein the lens satisfies the following conditional formula: 3 < TTL / f < 4; Wherein, TTL is the total optical length of the lens, and f is the focal length of the lens.

9. An electronic device, characterized in that, A low-distortion, large-target video conferencing lens according to any one of claims 1-8; and an image sensor configured to receive an image formed by the low-distortion, large-target video conferencing lens.

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