A video lens

Abstract

The application provides a video lens and relates to the technical field of optical lenses. The video lens comprises, in sequence from the object side to the image side along the optical axis, a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens. The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has negative optical power and the eighth lens has positive optical power. The embodiment of the application provides a video lens to realize a video lens system with small size, low distortion and high resolving power.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a video lens. Background Art

[0002] With the continuous advancement of internet technology, fixed-focus lenses are widely used in video conferencing, online teaching, and webcam recording, attracting increasing attention and demanding higher quality images. However, current video conferencing lenses on the market struggle to meet both high standards in size and distortion, making them difficult to meet the demands of diverse applications. The high-end market continues to see increasing demand for high-resolution, compact, and low-distortion lenses. Therefore, the design of compact, low-distortion, and high-resolution video lenses has become a market trend. Summary of the Invention

[0003] An embodiment of the present invention provides a video lens system to realize a small-sized, low-distortion, and high-resolution video lens system.

[0004] An embodiment of the present invention provides a video lens, comprising a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, arranged in sequence from the object side to the image side along an optical axis;

[0005] The optical focal power of the first lens is negative, the optical focal power of the second lens is negative, the optical focal power of the third lens is positive, the optical focal power of the fourth lens is positive, the optical focal power of the fifth lens is positive, the optical focal power of the sixth lens is negative, the optical focal power of the seventh lens is negative, and the optical focal power of the eighth lens is positive.

[0006] Optionally, the first lens is a glass spherical lens, the second lens is a plastic aspherical lens, the third lens is a glass spherical lens, the fourth lens is a plastic aspherical lens, the fifth lens is a glass spherical lens, the sixth lens is a glass spherical lens, the seventh lens is a plastic aspherical lens, and the eighth lens is a plastic aspherical lens.

[0007] Optionally, a surface of the first lens facing the object side is convex, and a surface of the first lens facing the image side is concave;

[0008] The surface of the second lens facing the object side is concave, and the surface of the second lens facing the image side is convex;

[0009] The surface of the third lens facing the object side is convex, and the surface of the third lens facing the image side is convex;

[0010] The surface of the fourth lens facing the object side is convex, and the surface of the fourth lens facing the image side is concave;

[0011] The surface of the fifth lens facing the object side is convex, and the surface of the fifth lens facing the image side is convex;

[0012] The surface of the sixth lens facing the object side is concave, and the surface of the sixth lens facing the image side is convex;

[0013] The surface of the seventh lens facing the object side is concave, and the surface of the seventh lens facing the image side is convex;

[0014] The surface of the eighth lens facing the object side is convex, and the surface of the eighth lens facing the image side is concave.

[0015] Optionally, the optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fourth lens is The optical power of the seventh lens is The optical power of the eighth lens is The combined optical power of the seventh lens and the eighth lens is The optical power of the video lens is Satisfies at least one of the following relationships:

[0016]

[0017] Optionally, the full aperture of the first lens is D1, and the total length of the video lens is TTL, satisfying the relationship: 0.325≤D1 / TTL≤0.355.

[0018] Optionally, the refractive index of the first lens is ND1, the Abbe number of the first lens is VD1, 1.380≤ND1≤1.645, 56.50≤VD1≤96.50;

[0019] and / or,

[0020] The object-side surface of the first lens has a curvature radius of S1, the image-side surface of the first lens has a curvature radius of S2, and 1.65≤(S1+S2) / (S1-S2)≤2.85.

[0021] Optionally, the fifth lens and the sixth lens form a doublet lens with positive optical power.

[0022] Optionally, the refractive index of the fifth lens is ND5, the Abbe number of the fifth lens is VD5, 1.35≤ND5≤1.65, 65.50≤VD5≤96.50;

[0023] and / or,

[0024] The optical power of the doublet lens is The optical power of the video lens is

[0025] Optionally, the center thickness of the second lens on the optical axis is d2, the center thickness of the fourth lens on the optical axis is d4, the center thickness of the seventh lens on the optical axis is d7, and the center thickness of the eighth lens on the optical axis is d8. The total optical length of the video lens is TTL, satisfying: 0.215≤(d2+d4+d7+d8) / TTL≤0.265.

[0026] Optionally, the total optical length of the video lens is TTL, the half image height of the video lens is H, and 4.285≤TTL / H≤4.325 is satisfied;

[0027] and / or,

[0028] The distance from the center of the image-side surface of the eighth lens to the center of the image plane is BFL, which satisfies the following: 0.195≤BFL / TTL≤0.215.

[0029] The video lens provided in an embodiment of the present invention includes eight lenses, and the optical powers of the first to eighth lenses are: negative, negative, positive, positive, positive, negative, negative, positive. The number of lenses is reasonable, the structure is simple and compact, and the optical power and position of each lens are reasonable, achieving a small size, low distortion, and high resolution. The video lens has an FNO of 1.90, a field of view of not less than 70°, an imaging target surface that can match a 1 / 2.7-inch chip, a total optical length of not more than 15mm, and an absolute value of optical distortion of not more than 2.5%, meeting the requirements of ultra-high-definition imaging. It can be used in video conferencing, online teaching, and network video shooting. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic structural diagram of a video camera provided in the first embodiment of the present invention;

[0031] Figure 2 A spherical aberration curve diagram provided in Example 1 of the present invention;

[0032] Figure 3 A light fan diagram provided in the first embodiment of the present invention;

[0033] Figure 4 A schematic diagram of field curvature provided in the first embodiment of the present invention;

[0034] Figure 5 A schematic diagram of distortion provided in Example 1 of the present invention;

[0035] Figure 6A schematic structural diagram of a video camera provided in the second embodiment of the present invention;

[0036] Figure 7 A spherical aberration curve diagram provided in Example 2 of the present invention;

[0037] Figure 8 A light fan diagram provided by the second embodiment of the present invention;

[0038] Figure 9 A schematic diagram of field curvature provided in the second embodiment of the present invention;

[0039] Figure 10 A schematic diagram of distortion provided in the second embodiment of the present invention;

[0040] Figure 11 A schematic structural diagram of a video camera provided in a third embodiment of the present invention;

[0041] Figure 12 A spherical aberration curve diagram provided in Example 3 of the present invention;

[0042] Figure 13 A light fan diagram provided by the third embodiment of the present invention;

[0043] Figure 14 A schematic diagram of field curvature provided in the third embodiment of the present invention;

[0044] Figure 15 A schematic diagram of distortion provided in the third embodiment of the present invention;

[0045] Figure 16 A schematic structural diagram of a video camera provided in a fourth embodiment of the present invention;

[0046] Figure 17 A spherical aberration curve diagram provided in the fourth embodiment of the present invention;

[0047] Figure 18 A light fan diagram provided by the fourth embodiment of the present invention;

[0048] Figure 19 A schematic diagram of field curvature provided in the fourth embodiment of the present invention;

[0049] Figure 20 A schematic diagram of distortion provided in the fourth embodiment of the present invention;

[0050] Figure 21 This is a schematic structural diagram of a video camera provided in a fifth embodiment of the present invention;

[0051] Figure 22 A spherical aberration curve diagram provided in Example 5 of the present invention;

[0052] Figure 23A light fan diagram provided by the fifth embodiment of the present invention;

[0053] Figure 24 A schematic diagram of field curvature provided in the fifth embodiment of the present invention;

[0054] Figure 25 A schematic diagram of distortion provided in the fifth embodiment of the present invention;

[0055] Figure 26 A schematic structural diagram of a video camera provided in a sixth embodiment of the present invention;

[0056] Figure 27 A spherical aberration curve diagram provided in Example 6 of the present invention;

[0057] Figure 28 A light fan diagram provided by embodiment 6 of the present invention;

[0058] Figure 29 A schematic diagram of field curvature provided in Example 6 of the present invention;

[0059] Figure 30 This is a distortion diagram provided in Example 6 of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0061] Example 1

[0062] Figure 1 This is a schematic diagram of the structure of a video lens provided in the first embodiment of the present invention, referring to Figure 1 The video lens includes a first lens 1, a second lens 2, an aperture STO, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, and an eighth lens 8, which are arranged in order from the object side to the image side along the optical axis. The first lens 1 has a negative optical power, the second lens 2 has a negative optical power, the third lens 3 has a positive optical power, the fourth lens 4 has a positive optical power, the fifth lens 5 has a positive optical power, the sixth lens 6 has a negative optical power, the seventh lens 7 has a negative optical power, and the eighth lens 8 has a positive optical power.

[0063] The aperture STO is located between the second lens element 2 and the third lens element 3 , which is beneficial for reducing the value of the aperture number FNO of the video lens.

[0064] The video lens provided by the embodiment of the application comprises eight lenses, and the focal lengths of the first lens 1 to the eighth lens 8 are: negative, negative, positive, positive, positive, negative, negative, and positive. The number of lenses is reasonable, the structure is simple and compact, the focal lengths and positions of the lenses are reasonable, and small size, low distortion, and high resolving power are achieved. The FNO of the video lens is 1.90, the field of view is not less than 70°, the imaging target surface can match a 1 / 2.7 inch chip, the total optical length is not greater than 15 mm, and the absolute value of optical distortion is not greater than 2.5%, which meets the requirements of ultra-high-definition imaging. The video lens can be used in the fields of video conferencing, online teaching, and network video shooting.

[0065] Optionally, with reference to Figure 1 , the first lens 1 is a glass spherical lens, the second lens 2 is a plastic aspherical lens, the third lens 3 is a glass spherical lens, the fourth lens 4 is a plastic aspherical lens, the fifth lens 5 is a glass spherical lens, the sixth lens 6 is a glass spherical lens, the seventh lens 7 is a plastic aspherical lens, and the eighth lens 8 is a plastic aspherical lens. The video lens provided by the embodiment of the application adopts 4G4P, that is, four glass spherical lenses and four plastic aspherical lenses, and through reasonable matching of the focal lengths, positions, and materials of the lenses, small size, low distortion, and high resolving power are achieved.

[0066] Optionally, with reference to Figure 1 , one side of the first lens 1 facing the object side is a convex surface, one side of the first lens 1 facing the image side is a concave surface, and the first lens 1 is a convex-concave lens. One side of the second lens 2 facing the object side is a concave surface, one side of the second lens 2 facing the image side is a convex surface, and the second lens 2 is a concave-convex lens. One side of the third lens 3 facing the object side is a convex surface, one side of the third lens 3 facing the image side is a convex surface, and the third lens 3 is a double-convex lens. One side of the fourth lens 4 facing the object side is a convex surface, one side of the fourth lens 4 facing the image side is a concave surface, and the fourth lens 4 is a convex-concave lens. One side of the fifth lens 5 facing the object side is a convex surface, one side of the fifth lens 5 facing the image side is a convex surface, and the fifth lens 5 is a double-convex lens. One side of the sixth lens 6 facing the object side is a concave surface, one side of the sixth lens 6 facing the image side is a convex surface, and the sixth lens 6 is a concave-convex lens. One side of the seventh lens 7 facing the object side is a concave surface, one side of the seventh lens 7 facing the image side is a convex surface, and the seventh lens 7 is a concave-convex lens. One side of the eighth lens 8 facing the object side is a convex surface, one side of the eighth lens 8 facing the image side is a concave surface, and the eighth lens 8 is a convex-concave lens. Through reasonable matching of the focal lengths, positions, shapes, and materials of the lenses, small size, low distortion, and high resolving power are achieved.

[0067] Optionally, with reference to Figure 1 , the focal length of the first lens 1 is The focal length of the second lens 2 is The focal length of the third lens 3 is The focal length of the fourth lens 4 is The optical power of the seventh lens 7 is The optical power of the eighth lens 8 is The combined optical power of the seventh lens 7 and the eighth lens 8 is The optical power of the video lens is Satisfies at least one of the following relationships:

[0068] For example, the first lens 1 is designed as a meniscus-shaped negative lens with its convex surface facing the object side, and the optical power of the first lens 1 is The optical power of the video lens is satisfy In this way, light with a large field of view can enter the video lens as much as possible, which is beneficial to increasing the field of view angle of the video lens.

[0069] Optionally, refer to Figure 1 The full aperture of the first lens 1 is D1, and the total length of the video lens is TTL, which satisfies the relationship: 0.325≤D1 / TTL≤0.355. This is conducive to reducing the size of the video lens and achieving miniaturization of the video lens.

[0070] Optionally, refer to Figure 1 The refractive index of the first lens element 1 is ND1, and the Abbe number of the first lens element 1 is VD1. 1.380≤ND1≤1.645, 56.50≤VD1≤96.50. The chromatic aberration of the video lens can be improved by rationally allocating the Abbe number of the first lens element 1.

[0071] Optionally, refer to Figure 1 , the object-side curvature radius of the first lens 1 is S1, the image-side curvature radius of the first lens 1 is S2, and 1.65≤(S1+S2) / (S1-S2)≤2.85. The object-side surface refers to the surface of the lens (e.g., the first lens 1) facing the object side, i.e., the front surface. The image-side surface refers to the surface of the lens (e.g., the first lens 1) facing the image side, i.e., the back surface. Setting 1.65≤(S1+S2) / (S1-S2)≤2.85 can help converge light from different fields of view and improve image brightness.

[0072] For example, the second lens 2 is designed as a concave-convex negative lens, and the optical power of the second lens 2 is The optical power of the video lens is satisfy: On the one hand, it can effectively control the direction of light, reduce the field curvature and spherical aberration of the video lens, and improve the image quality of the optical video lens; on the other hand, by designing the second lens 2 as a concave-convex aspheric lens symmetrical to the first lens 1, the purpose of low distortion design can be achieved.

[0073] For example, the third lens 3 is designed as a biconvex positive lens. The third lens 3 is located after the aperture STO, which can effectively control the light to smoothly enter the rear of the video lens, reduce the spherical aberration of the video lens, and improve the imaging quality of the video lens. The optical power of the third lens 3 is The optical power of the video lens is satisfy This is advantageous in balancing the light aberration in front of the aperture STO.

[0074] For example, the fourth lens element 4 is designed as a meniscus-shaped negative lens with its convex surface facing the object side, and the optical power of the fourth lens element 4 is The optical power of the video lens is This can help control the direction of light, reduce the angle of light deflection, reduce the system sensitivity of the video lens, and help improve production yield.

[0075] Optionally, refer to Figure 1 , the fifth lens 5 and the sixth lens 6 form a doublet lens with positive optical power.

[0076] Furthermore, the optical power of the doublet lens is The optical power of the video lens is The refractive index of the fifth lens element 5 is ND5, and the Abbe number of the fifth lens element 5 is VD5, where 1.35≤ND5≤1.65 and 65.50≤VD5≤96.50. By using a doublet lens material and properly adjusting the optical power of the doublet lens, chromatic aberration is balanced, improving imaging quality. It also smoothly transmits light, reduces tolerance sensitivity, and improves assembly yield.

[0077] For example, the seventh lens 7 is designed as a concave-convex negative lens, and the eighth lens 8 is designed as a convex-concave positive lens. The seventh lens 7 and the eighth lens 8 are symmetrically arranged, which can effectively control the direction of light, increase the direction of light, meet the image size requirements and improve the illumination. The optical power of the seventh lens 7 is The optical power of the eighth lens 8 is The optical power of the video lens is satisfy: This is beneficial for controlling aberrations, reducing tolerance sensitivity, and improving image quality. The combined optical power of the seventh lens 7 and the eighth lens 8 is The optical power of the video lens is satisfy: This can effectively correct optical distortion, making the absolute value of optical distortion less than or equal to 2.5%, while improving the optical imaging performance of the optical video lens.

[0078] Illustratively, a filter 9 is provided on the side of the eighth lens 8 facing the image plane IMA, and light enters through the filter 9. Considering that a CMOS photosensitive chip will be used when applied to lens imaging, the filter 9 has a certain protective effect on the photosensitive chip. At the same time, it also filters part of the light to reduce stray light, so that the image color is bright and sharp while having good color reproduction.

[0079] Optionally, refer to Figure 1 The center thickness of the second lens element 2 on the optical axis is d2, the center thickness of the fourth lens element 4 on the optical axis is d4, the center thickness of the seventh lens element 7 on the optical axis is d7, and the center thickness of the eighth lens element 8 on the optical axis is d8. The total optical length (TTL) of the video lens satisfies the following: 0.215 ≤ (d2 + d4 + d7 + d8) / TTL ≤ 0.265. This improves the machinability of each lens element and helps reduce the sensitivity of the video lens. It also helps reduce the air gap between the lenses, thereby shortening the total optical length of the video lens, achieving a TTL of ≤ 15 mm.

[0080] Optionally, refer to Figure 1 The total optical length of the video lens is TTL, and the half-image height of the video lens is H, which satisfies 4.285≤TTL / H≤4.325. When the image height is constant, properly setting the total optical length of the video lens is conducive to achieving miniaturization of the video lens.

[0081] Furthermore, the distance between the center of the image-side surface of the eighth lens element 8 and the center of the image plane IMA is BFL, and the total optical length of the video lens is TTL, satisfying the following relationship: 0.195 ≤ BFL / TTL ≤ 0.215. This improves the assembly yield of the video lens, helps reserve space for the installation of optical components, and facilitates assembly of the video lens.

[0082] Table 1: Design values ​​of the video lens in Example 1

[0083]

[0084] Table 1 shows a design value of the video lens in Example 1. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 1 can be Figure 1As shown in . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the order of the surfaces of each lens. Among them, surface number 1 represents the front surface of the first lens 1 (i.e., the object side), surface number 2 represents the back surface of the first lens 1 (i.e., the image side), and so on, which will not be repeated here. "STO" represents the aperture. The units of curvature radius, thickness and semi-aperture are all mm. The curvature radius represents the degree of curvature of the corresponding lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. "INF" represents that the surface is a plane and the curvature radius is infinite. Thickness represents the axial distance from the center of the current surface to the next surface. The refractive index represents the ability of the material between the current surface and the next surface to refract light. A blank space represents that the current position is air and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air. The value in the semi-aperture column represents the half-height of the light corresponding to the current surface. k is the conic section constant.

[0085] Table 2: Design values ​​of aspheric coefficients of the lens in the video lens in Example 1

[0086]

[0087] Table 2 shows a design value of the aspheric coefficient of the lens in the video lens of Example 1. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 2 can be Figure 1 The meaning of the column "surface number" in Table 2 is consistent with that in Table 1. "E" in each embodiment of the present invention represents an exponent with base 10.

[0088] Optionally, the surface of the aspheric lens satisfies the formula:

[0089]

[0090] Among them, z is the axial sagittal height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the curvature radius; k is the fitted cone coefficient; A, B, C, D, E, and F are the coefficients of the 4th, 6th, 8th, 10th, 12th, and 14th order terms of the aspheric polynomial.

[0091] For example, in the first embodiment, the focal length f is 5.045 mm, the F# (ie, the aperture number FNO) is 1.90, the field of view angle DFOV=70°, the total optical length TTL: 14.89 mm; and the optical distortion: -2.0%.

[0092] For example, in embodiment 1, D1 / TTL=0.349; ND1=1.517; VD1=64.212; (S1+S2) / (S1-S2)=2.213; ND5=1.497;VD5=81.61; (d2+d4+d7+d8) / TTL=0.241; TTL / H=4.302; BFL / TTL=0.205.

[0093] Figure 2 A spherical aberration curve diagram provided in Example 1 of the present invention, referring to Figure 2 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging, which are represented by Figure 2 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the video lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0094] Figure 3 A light fan diagram is provided in the first embodiment of the present invention, referring to Figure 3 The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam diameter, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays are focused on the same point on the image plane. The corresponding interval on the vertical axis of the curve is the maximum diffusion range of the light beam on the ideal image plane. The ray fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. Figure 3 It can be seen that the video lens's wavelengths in all fields of view are well aligned with the horizontal axis, indicating that the system's vertical aberrations at each wavelength are well corrected. At the same time, there is no noticeable dispersion across the wavelengths, indicating that the video lens's chromatic aberrations are also well corrected, thus ensuring that the video lens can achieve high-resolution imaging requirements.

[0095] Figure 4 This is a schematic diagram of field curvature provided in the first embodiment of the present invention, with reference to Figure 4 , the horizontal coordinate represents the magnitude of field curvature, the unit is mm; the vertical coordinate represents the normalized image height, no unit; T represents the meridian, S represents the sagittal; by Figure 4 It can be seen that the video lens provided in this embodiment effectively controls the field curvature from light with a wavelength of 436nm to light with a wavelength of 650nm. That is, during imaging, the difference in image quality between the center and the periphery is small.

[0096] Figure 5 This is a distortion diagram provided in Example 1 of the present invention, refer to Figure 5 , the horizontal coordinate represents the size of the distortion, the unit is %; the vertical coordinate represents the normalized image height, no unit; Figure 5 It can be seen that the distortion of the lens in this embodiment is relatively small.

[0097] Example 2

[0098] Similarities with the above embodiment are not repeated here.

[0099] Table 2: Design values ​​of the video lens in Example 2

[0100]

[0101] Table 3 shows a design value of the video lens in Example 2. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. Figure 6 As shown in .

[0102] Table 4: A design value of the aspheric coefficient of the lens in the video lens of Example 2

[0103]

[0104] Table 4 shows a design value of the aspheric coefficient of the lens in the video lens of Example 2. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 4 can be Figure 6 As shown in .

[0105] For example, in the second embodiment, the focal length f is 4.972 mm, the F# (ie, the aperture number FNO) is 1.90, the field of view angle DFOV=70°, the total optical length TTL: 14.90 mm; and the optical distortion: -1.84%.

[0106] For example, in the second embodiment, D1 / TTL=0.348; ND1=1.593; VD1=68.346; (S1+S2) / (S1-S2)=2.409; ND5=1.497;VD5=81.61; (d2+d4+d7+d8) / TTL=0.245; TTL / H=4.319; BFL / TTL=0.208.

[0107] Example 3

[0108] Similarities with the above embodiment are not repeated here.

[0109] Table 5: Design values ​​of the video lens in Example 3

[0110]

[0111] Table 5 shows a design value of the video lens in Example 3. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 5 can be Figure 11 As shown in .

[0112] Table 6: A design value of the aspheric coefficient of the lens in the video lens of Example 3

[0113]

[0114] Table 6 shows a design value of the aspheric coefficient of the lens in the video lens of Example 3. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 6 can be Figure 11 As shown in .

[0115] For example, in Example 3, the focal length f is 4.95 mm, the F# (ie, the aperture number FNO) is 1.90, the field of view angle DFOV=70°, the total optical length TTL: 14.90 mm; and the optical distortion: 1.99%.

[0116] For example, in Example 3, D1 / TTL=0.352; ND1=1.438; VD1=94.577; (S1+S2) / (S1-S2)=1.751; ND5=1.497;VD5=81.61; (d2+d4+d7+d8) / TTL=0.250; TTL / H=4.319; BFL / TTL=0.208.

[0117] Example 4

[0118] Similarities with the above embodiment are not repeated here.

[0119] Table 7: Design values ​​of the video lens in Example 4

[0120]

[0121] Table 7 shows a design value of the video lens in the fourth embodiment. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 7 can be Figure 16 As shown in .

[0122] Table 8: Design values ​​of aspheric coefficients of the lens in the video lens in Example 4

[0123]

[0124] Table 8 shows a design value of aspheric coefficients of the lens in the video lens in Example Four, and the specific numerical size can be adjusted according to product requirements, which is not a limitation of the embodiments of the present application. The video lens shown in Table 8 can be shown in the following table. Figure 16

[0125] Exemplarily, in Example Four, the focal length f is 4.89 mm, the F# (i.e. the aperture number FNO) is 1.90, the field of view angle DFOV = 70°, the total optical length TTL: 14.90 mm; the optical distortion: -1.31%.

[0126] Exemplarily, in Example Four, D1 / TTL = 0.343; ND1 = 1.593; VD1 = 68.346; (S1 + S2) / (S1 - S2) = 2.076; ND5 = 1.497; VD5 = 81.61; (d2 + d4 + d7 + d8) / TTL = 0.236; TTL / H = 4.319; BFL / TTL = 0.208.

[0127] Example Five

[0128] Similar to the above embodiments, details are not repeated here.

[0129] Table 9 shows a design value of the video lens in Example Five

[0130]

[0131] Table 9 shows a design value of the video lens in Example Five, and the specific numerical size can be adjusted according to product requirements, which is not a limitation of the embodiments of the present application. The video lens shown in Table 9 can be shown in the following table. Figure 21

[0132] Table 10 shows a design value of aspheric coefficients of the lens in the video lens in Example Five

[0133]

[0134] Table 10 shows a design value of aspheric coefficients of the lens in the video lens in Example Five, and the specific numerical size can be adjusted according to product requirements, which is not a limitation of the embodiments of the present application. The video lens shown in Table 10 can be shown in the following table. Figure 21

[0135] ​​​For example, in Example 5, the focal length f is 4.95 mm, the F# (ie, the aperture number FNO) is 1.90, the field of view angle DFOV=70°, the total optical length TTL: 14.90 mm; and the optical distortion: -1.61%.

[0136] For example, in Example 5, D1 / TTL=0.344; ND1=1.593; VD1=68.346; (S1+S2) / (S1-S2)=2.384; ND5=1.437;VD5=95.10; (d2+d4+d7+d8) / TTL=0.245; TTL / H=4.319; BFL / TTL=0.208.

[0137] Example 6

[0138] Similarities with the above embodiment are not repeated here.

[0139] Table 11: Design values ​​of the video lens in Example 6

[0140]

[0141] Table 11 shows a design value of the video lens in Example 6. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 11 can be Figure 26 As shown in .

[0142] Table 12: Design values ​​of aspheric coefficients of the lens in the video lens in Example 6

[0143]

[0144] Table 12 shows a design value of the aspheric coefficient of the lens in the video lens of Example 6. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The video lens shown in Table 12 can be Figure 26 As shown in .

[0145] For example, in Example 6, the focal length f is 4.98 mm, the F# (ie, the aperture number FNO) is 1.90, the field of view angle DFOV=70°, the total optical length TTL: 14.90 mm; and the optical distortion: -2.20%.

[0146] For example, in Example 6, D1 / TTL=0.343; ND1=1.593; VD1=68.346; (S1+S2) / (S1-S2)=2.615; ND5 = 1.593; VD5 = 68.62; (d2+d4+d7+d8) / TTL = 0.235; TTL / H = 4.320; BFL / TTL = 0.210.

[0147] It is to be understood, therefore, that even though certain embodiments of the application have been specifically discussed, the present application includes all modifications and equivalents of those embodiments falling within the scope of the appended claims.

Claims

1. A video camera, characterized in that: It consists of a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence from the object side to the image side along the optical axis; The optical power of the first lens is negative, the optical power of the second lens is negative, the optical power of the third lens is positive, the optical power of the fourth lens is positive, the optical power of the fifth lens is positive, the optical power of the sixth lens is negative, the optical power of the seventh lens is negative, and the optical power of the eighth lens is positive; The optical power of the first lens is φ1, the optical power of the second lens is φ2, the optical power of the third lens is φ3, the optical power of the eighth lens is φ8, and the optical power of the video lens is φ, which satisfies the following relationship: -0.75≤φ1 / φ≤-0.55; -0.205≤φ2 / φ≤-0.010; 0.75≤φ3 / φ≤1.05; 0.25≤φ8 / φ≤0.

365.

2. The video camera according to claim 1, wherein: The first lens is a glass spherical lens, the second lens is a plastic aspherical lens, the third lens is a glass spherical lens, the fourth lens is a plastic aspherical lens, the fifth lens is a glass spherical lens, the sixth lens is a glass spherical lens, the seventh lens is a plastic aspherical lens, and the eighth lens is a plastic aspherical lens.

3. The video camera according to claim 1, wherein: The surface of the first lens facing the object side is convex, and the surface of the first lens facing the image side is concave; The surface of the second lens facing the object side is concave, and the surface of the second lens facing the image side is convex; The surface of the third lens facing the object side is convex, and the surface of the third lens facing the image side is convex; The surface of the fourth lens facing the object side is convex, and the surface of the fourth lens facing the image side is concave; The surface of the fifth lens facing the object side is convex, and the surface of the fifth lens facing the image side is convex; The surface of the sixth lens facing the object side is concave, and the surface of the sixth lens facing the image side is convex; The surface of the seventh lens facing the object side is concave, and the surface of the seventh lens facing the image side is convex; The surface of the eighth lens facing the object side is convex, and the surface of the eighth lens facing the image side is concave.

4. The video camera according to claim 1, wherein: The focal power of the fourth lens is φ4, the focal power of the seventh lens is φ7, and the combined focal power of the seventh lens and the eighth lens is φ78, satisfying at least one of the following relationships: 0.01≤φ4 / φ≤0.15; -0.305≤φ7 / φ≤-0.05; 0.025≤φ78 / φ≤0.

185.

5. The video camera according to claim 1, wherein: The full aperture of the first lens is D1, and the total length of the video lens is TTL, which satisfies the relationship: 0.325≤D1 / TTL≤0.

355.

6. The video camera according to claim 1, wherein: The refractive index of the first lens is ND1, the Abbe number of the first lens is VD1, 1.380≤ND1≤1.645, 56.50≤VD1≤96.50; and / or, The object-side surface of the first lens has a curvature radius of S1, the image-side surface of the first lens has a curvature radius of S2, and 1.65≤(S1+S2) / (S1-S2)≤2.

85.

7. The video camera according to claim 1, wherein: The fifth lens and the sixth lens form a doublet lens with positive refractive power.

8. The video camera according to claim 7, wherein: The refractive index of the fifth lens is ND5, and the Abbe number of the fifth lens is VD5, 1.35≤ND5≤1.65, 65.50≤VD5≤96.50; and / or, The optical power of the doublet lens is φ56, 0.245≤φ56 / φ≤0.

45.

9. The video camera according to claim 1, wherein: The center thickness of the second lens on the optical axis is d2, the center thickness of the fourth lens on the optical axis is d4, the center thickness of the seventh lens on the optical axis is d7, and the center thickness of the eighth lens on the optical axis is d8. The total optical length of the video lens is TTL, which satisfies the following: 0.215≤(d2+d4+d7+d8) / TTL≤0.

265.

10. The video camera according to claim 1, wherein: The total optical length of the video lens is TTL, the half image height of the video lens is H, and 4.285≤TTL / H≤4.325 is satisfied; and / or, The distance between the center of the image-side surface of the eighth lens and the center of the image plane is BFL, which satisfies: 0.195≤BFL / TTL≤0.215.

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