Optical systems, video optical lenses and video equipment

Abstract

The present invention discloses an optical system, a video optical lens and a video device, and relates to the technical field of optical lenses. The optical system has an object side and an image side that are relatively arranged along the optical axis, including a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens and a seventh lens, a protective sheet and a photosensitive chip that are arranged in sequence from the object side to the image side. The optical focal length of the optical system is FA, and the imaging height of the optical system is IH, which satisfies the following relationship: 0.2≤FA / IH≤0.35. By designing each lens accordingly, the HFOV of the optical system is not less than 110°, the imaging viewing angle is large, and a wider field of view can be provided; the resolution reaches 4K, ensuring the imaging quality; the distortion is small, the TV distortion reaches less than 3%, the picture effect is better, and the back-end engineering does not need to do distortion correction.

Description

Technical Field

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

[0002] With the rapid development of the world's economic globalization, people's demand for video transmission is increasing day by day. Video transmission has been widely used in various departments such as government, military, medical care, and education, providing a reliable guarantee for the rapid development of globalization.

[0003] Currently, conference video cameras require a 16:9 chip with an HFOV of 110° or higher, and TV distortion below 5%, achieving 4K HD quality. There are several similar video cameras on the market, each with some compromises. There are two main types: one with a horizontal angle of 100-105° and TV distortion below 5%, and one with a horizontal angle of 110° or higher and TV distortion of 7% to 10%. Some cameras may compromise both, and it is generally impossible to achieve all three simultaneously. Summary of the Invention

[0004] The main purpose of the present invention is to provide an optical system and video equipment, aiming to solve the technical problem that existing video lenses cannot simultaneously meet the requirements of large horizontal viewing angle, high imaging resolution and low distortion level.

[0005] To achieve the above objectives, the present invention provides an optical system for adapting to an imaging chip with an aspect ratio of 16:9. The optical system has an object side and an image side disposed opposite each other along the optical axis, and includes, arranged in order from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, an aperture stop, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, a protective sheet, and a photosensitive chip.

[0006] The optical focal length of the optical system is FA, and the imaging height of the optical system is IH, which satisfies the following relationship:

[0007] 0.2≤FA / IH≤0.35.

[0008] Optionally, the first lens is a meniscus lens, the second lens is a meniscus lens, the third lens is a biconcave lens, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, and the seventh lens is a biconvex lens;

[0009] The concave surfaces of the first lens and the second lens face the image side.

[0010] Optionally, the second lens, the third lens, the fifth lens, the sixth lens and the seventh lens are plastic lenses.

[0011] Optionally, the first lens is a glass lens or a plastic lens; and / or,

[0012] The fourth lens is a glass lens.

[0013] Optionally, the refractive index of the fourth lens is nd4, and the Abbe number is vd4, which satisfy the following relationship:

[0014] 1.84≤nd4≤2.01, and / or, 19≤vd4≤40.

[0015] Optionally, the refractive index of the third lens is nd3, and the Abbe number is vd3, which satisfy the following relationship:

[0016] 1.6≤nd3≤1.75, and / or, 19≤vd3≤25.

[0017] Optionally, the refractive index of the second lens, the fifth lens, and the seventh lens are all nd257, and the Abbe number of the second lens, the fifth lens, and the seventh lens are all vd257, satisfying the following relationship:

[0018] 1.45≤nd257≤1.6, and / or, 50≤vd257≤60.

[0019] Optionally, the focal length of the first lens is φ1, -19<φ1<-15mm; and / or,

[0020] The focal length of the second lens is φ2, -3.5<φ2<-6mm; and / or,

[0021] The focal length of the third lens is φ3, -14<φ3<-10mm; and / or,

[0022] The focal length of the fourth lens is φ4, 3<φ4<6mm; and / or,

[0023] The focal length of the fifth lens is φ5, 1<φ5<5mm; and / or,

[0024] The focal length of the sixth lens is φ6, -1<φ6<-5mm; and / or,

[0025] The focal length of the seventh lens is φ7, 2<φ7<6mm.

[0026] The present invention further provides a video optical lens, comprising a lens body, wherein the direction from the object side to the image side along the optical axis of the lens body is from front to back, and the lens body comprises:

[0027] a lens barrel arranged in a front-to-rear direction, wherein a cavity is formed in the lens barrel; and

[0028] The optical system as described above is arranged in the cavity.

[0029] The present invention further provides a video device, which includes a video optical lens, and the video optical lens includes the optical system as described above.

[0030] In the technical solution provided by the present invention, the optical system has an object side and an image side arranged relative to each other along the optical axis, and includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, an aperture, a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power, a protective sheet, and a photosensitive chip. The optical focal length of the optical system is FA, and the imaging height of the optical system is IH, which satisfies the following relationship: 0.2≤FA / IH≤0.35. Compared with the background technology, the technical solution of the present invention, through the corresponding design of each lens, makes the optical system's HFOV no less than 110°, with a large imaging angle of view, providing a wider field of view; the resolution reaches 4K, ensuring image quality; the distortion is small, with TV distortion below 3%, and the picture effect is better, avoiding the need for distortion correction in the back-end engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0032] Figure 1 A schematic structural diagram of an embodiment of an optical system provided by the present invention;

[0033] Figure 2 for Figure 1 MTF curve diagram of the optical system in;

[0034] Figure 3 for Figure 1 Point diagram of the optical system in ;

[0035] Figure 4 for Figure 1 Field curvature diagram of the optical system in ;

[0036] Figure 5 for Figure 1 Distortion diagram of the optical system in .

[0037] Description of Figure Numbers:

[0038]

[0039]

[0040] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0044] Currently, conference video cameras require a 16:9 chip with an HFOV of 110° or higher, and distortion below 5%, achieving 4K HD quality. There are several similar video cameras on the market, each with some compromises. There are two main types: one with a horizontal angle of 100-105° and TV distortion below 5%, and one with a horizontal angle of 110° or higher and TV distortion of 7% to 10%. Some cameras may compromise both, and it's generally impossible to achieve all three simultaneously.

[0045] In view of this, the present invention proposes an optical system that aims to solve the technical problem that existing video lenses cannot simultaneously meet the requirements of a large horizontal viewing angle, high imaging resolution, and low distortion level. The optical system is adapted for use with a 16:9 chip. The optical system has an object side and an image side disposed opposite each other along the optical axis. The optical system includes a first lens 1 with negative optical power, a second lens 2 with negative optical power, a third lens 3 with negative optical power, a fourth lens 4 with positive optical power, an aperture 8, a fifth lens 5 with positive optical power, a sixth lens 6 with negative optical power, and a seventh lens 7 with positive optical power, a protective sheet, and a photosensitive chip 11. The optical focal length of the optical system is FA, and the imaging height of the optical system is IH, satisfying the following relationship:

[0046] 0.2≤FA / IH≤0.35.

[0047] The technical solution of the present invention makes the HFOV of the optical system no less than 110° through corresponding design of each lens, and the imaging viewing angle is large, which can provide a wider field of view; the resolution reaches 4K, ensuring the imaging quality; the distortion is small, and the TV distortion is less than 3%, which has a better picture effect and avoids the need for distortion correction in the back-end engineering.

[0048] By setting the first lens 1 and the second lens 2 with negative optical power, the astigmatism and field curvature of large-angle light can be corrected, so that the light entering the rear group has a smaller angle and residual aberration; the third lens 3 corrects distortion and dispersion, so that the system has small distortion; the fourth lens 4 can increase the height of the light entering the rear group, so that the system has a larger aperture; the aperture 8 limits the aperture of the on-axis light beam and blocks part of the light during the zooming process, reducing the light spot, improving the image contrast, and helping to improve the image quality; the fifth lens 5 and the sixth lens 6 can correct the chromatic aberration of the system, so that the aberration of the system can be adapted to the video system; the seventh lens 7 can correct the residual spherical aberration of the system and further correct the distortion of the system, so that high-quality imaging is obtained on the photosensitive chip 11, and the third lens 3, the fifth lens 5, the sixth lens 6 and the seventh lens 7 form focal length compensation, so that the entire system has no thermal focus deviation phenomenon.

[0049] Furthermore, a protective sheet is provided between the photosensitive chip 11 and the seventh lens. The protective sheet is made of transparent glass and can isolate and protect the photosensitive chip 11. In this embodiment, the protective sheet includes a first protective sheet 9 and a second protective sheet 10. The second protective sheet 10 is a glass sheet provided by the photosensitive chip 11. The first protective sheet 9 is provided on the side of the second protective sheet 10 facing the magnifying end to further improve the protection of the image source.

[0050] Furthermore, the first lens 1 is a meniscus lens, the second lens 2 is a meniscus lens, the third lens 3 is a biconcave lens, the fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconvex lens, the sixth lens 6 is a biconcave lens, and the seventh lens 7 is a biconvex lens; wherein the concave surfaces of the first lens 1 and the second lens 2 face backwards.

[0051] In one embodiment of the present invention, at least one of the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7 is configured as a plastic lens. Plastic lenses have strong impact resistance, are lightweight, and are low in cost. In addition, plastic lenses have better light transmittance.

[0052] It should be noted that, in other embodiments, the second lens 2 , the third lens 3 , the fifth lens 5 , the sixth lens 6 and the seventh lens 7 may also be glass lenses.

[0053] In the embodiment of the present invention, the second lens 2, the third lens 3, the fifth lens 5, the sixth lens 6, and the seventh lens 7 are aspheric lenses. The use of plastic aspheric lenses effectively controls costs and effectively corrects lens chromatic aberration, achieving infrared confocality while ensuring control of lens purple fringing. Spherical aberration and sine aberration at high magnification positions are also corrected.

[0054] In one embodiment of the present invention, the first lens 1 is a glass lens or a plastic lens. A glass lens has a higher transmittance. A plastic lens ensures the transmittance of the first lens 1 and has a strong impact resistance, effectively protecting other lenses located behind it. And / or, the fourth lens 4 is a glass lens. The fourth lens 4 is a glass lens to ensure that the optical system can produce clear images in environments with high temperatures below 80°C and low temperatures above -40°C.

[0055] In one embodiment of the present invention, the refractive index of the fourth lens 4 is nd4, and the Abbe number is vd4, which satisfies the following relationship:

[0056] 1.84≤nd4≤2.01, and / or, 19≤vd4≤40.

[0057] In one embodiment of the present invention, the refractive index of the third lens 3 is nd3, and the Abbe number is vd3, which satisfies the following relationship:

[0058] 1.6≤nd3≤1.75, and / or, 19≤vd3≤25.

[0059] In one embodiment of the present invention, the refractive index of the second lens 2, the fifth lens 5, and the seventh lens 7 are all nd257, and the Abbe number of the second lens 2, the fifth lens 5, and the seventh lens 7 are all vd257, satisfying the following relationship:

[0060] 1.45≤nd257≤1.6, and / or, 50≤vd257≤60.

[0061] In an embodiment of the present invention, the focal length of the first lens 1 is φ1, -19<φ1<-15mm; and / or the focal length of the second lens 2 is φ2, -3.5<φ2<-6mm; and / or the focal length of the third lens 3 is φ3, -14<φ3<-10mm; and / or the focal length of the fourth lens 4 is φ4, 3<φ4<6mm; and / or the focal length of the fifth lens 5 is φ5, 1<φ5<5mm; and / or the focal length of the sixth lens 6 is φ6, -1<φ6<-5mm; and / or the focal length of the seventh lens 7 is φ7, 2<φ7<6mm.

[0062] Specifically, in this embodiment, the surface shape, curvature radius and thickness of the lens are shown in the following table:

[0063] Table 1

[0064] Face number Face shape Radius / mm Thickness / mm Optical Materials OBJ standard Infinity 1000 S1 standard 10.53833 0.9850492 1.612，58.60 S2 standard 5.140717 2.135928 S3 Aspheric 11.50919 1.071537 1.535,55.63 S4 Aspheric 2.014063 2.96317 S5 Aspheric -15.62692 0.7933691 1.67,19.3 S6 Aspheric 20.72504 0.09742519 S7 standard 6.091552 4.322018 1.93,23.95 S8 standard -11.77466 1.571285 STO standard Infinity 0.1866025 S10 Aspheric 5.664612 1.373847 1.535,55.63 S11 Aspheric -2.180501 0.0497191 S12 Aspheric -1.857984 0.6687726 1.64,23.5 S13 Aspheric 29.82884 0.5268166 S14 Aspheric 3.528634 2.637496 1.535,55.63 S15 Aspheric -5.468886 0.1832668 S16 standard Infinity 0.3 1.516,64.2 S17 standard Infinity 1.6 S18 standard Infinity 0.4 1.516,64.2 S19 standard Infinity 0.504923 IMA standard Infinity -

[0065] Furthermore, in this embodiment, the aspheric surface shape of the aspheric lens satisfies the following conditions:

[0066]

[0067] Where c is the curvature corresponding to the radius, y is the radial coordinate (its unit is the same as the lens length unit), and k is the conic coefficient (when the k coefficient is less than -1, the surface curve is a hyperbola, when the k coefficient is equal to -1, it is a parabola, when the k coefficient is between -1 and 0, it is an ellipse, when the k coefficient is equal to 0, it is a circle, and when the k coefficient is greater than 0, it is an oblate). Please refer to Table 2 below. The above parameters can be used to set the shape and size of the lens's object side and image side aspheric surfaces.

[0068] Table 2 Conic coefficients and aspheric coefficients corresponding to aspheric lenses

[0069]

[0070] Figure 2 Displaying an MTF graph of the optical system; Figure 3 Display a spot diagram (SPOT) of the optical system; Figure 4 is a field curvature diagram of the optical system; Figure 5 is the distortion diagram of the optical system.

[0071] As can be seen from the above figure, the technical solution of the present invention can effectively reduce various chromatic aberration parameters by designing each lens accordingly; the HFOV of the optical system is made not less than 110°, the imaging viewing angle is large, and a wider field of view can be provided; the resolution reaches 4K, ensuring the imaging quality; the distortion is small, and the TV distortion is less than 3%, the picture effect is better, and the back-end engineering does not need to perform distortion correction; and infrared confocal can be achieved.

[0072] The present invention also provides a video optical lens, which includes a lens body. The direction along the optical axis of the lens body from the object side to the image side is from front to back. The lens body includes a lens barrel and the optical system described in the above technical solution. The lens barrel is arranged in the front-to-back direction. A cavity is formed in the barrel. The optical system is arranged in the cavity. Since the video optical lens includes the optical system, the specific structure of the optical system refers to the above embodiment. Since the optical system of this video optical lens adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0073] In addition, the present invention also provides a video device, which includes the video optical lens described in the above technical solution. Since the video device includes the video optical lens, the specific structure of the video optical lens refers to the above embodiment. Since the optical system of this video device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0074] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An optical system for adapting to a camera chip with an aspect ratio of 16:9, characterized in that: The optical system has an object side and an image side arranged opposite to each other along the optical axis, and includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, an aperture, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, a protective sheet, and a photosensitive chip. The optical focal length of the optical system is FA, and the imaging height of the optical system is IH, which satisfies the following relationship: 0.2≤FA / IH≤0.35; The first lens is a meniscus lens, the second lens is a meniscus lens, the third lens is a biconcave lens, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, and the seventh lens is a biconvex lens; Wherein, the concave surfaces of the first lens and the second lens face the image side; The refractive index nd1 of the first lens is 1.612; the Abbe number vd1 is 58.60; the front side of the first lens is a spherical surface with a radius of 10.53833 mm and a thickness of 0.9850492 mm; The rear side of the first lens is a spherical surface with a radius of 5.140717 mm and a thickness of 2.135928 mm; The refractive index nd2 of the second lens is 1.535, the Abbe number vd2 is 55.63, the front side of the second lens is aspherical, the radius is 11.50919 mm, and the thickness is 1.071537 mm; The rear side of the second lens is aspherical, with a radius of 2.014063 mm and a thickness of 2.96317 mm; The refractive index nd3 of the third lens is 1.67, the Abbe number vd3 is 19.3, the front side of the third lens is aspherical, the radius is -15.62692 mm, and the thickness is 0.7933691 mm; The rear surface of the third lens is aspherical, with a radius of 20.72504mm and a thickness of 0.09742519mm; The refractive index nd4 of the fourth lens is 1.93, the Abbe number vd4 is 23.95, the front side of the fourth lens is a spherical surface, the radius is 6.091552 mm, and the thickness is 4.322018 mm; The rear side surface of the fourth lens is a spherical surface with a radius of -11.77466 mm and a thickness of 1.571285 mm; The refractive index nd5 of the fifth lens is 1.535, the Abbe number vd5 is 55.63, the front side of the fifth lens is aspherical, the radius is 5.664612 mm, and the thickness is 1.373847 mm; The rear side surface of the fifth lens is aspherical, with a radius of -2.180501 mm and a thickness of 0.0497191 mm; The refractive index nd6 of the sixth lens is 1.64, the Abbe number vd6 is 23.5, the front side of the sixth lens is aspherical, the radius is -1.857984 mm, and the thickness is 0.6687726 mm; The rear side surface of the sixth lens is aspherical, with a radius of 29.82884 mm and a thickness of 0.5268166 mm; The refractive index nd7 of the seventh lens is 1.535, and the Abbe number vd7 is 55.63; the front side of the seventh lens is aspherical, with a radius of 3.528634 mm and a thickness of 2.637496 mm; The rear side surface of the seventh lens is aspherical, with a radius of -5.468886 mm and a thickness of 0.1832668 mm.

2. The optical system according to claim 1, wherein The second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are plastic lenses.

3. The optical system according to claim 1, wherein The first lens is a glass lens or a plastic lens; and / or, The fourth lens is a glass lens.

4. The optical system according to claim 1, wherein The refractive index of the fourth lens is nd4, and the Abbe number is vd4, which satisfies the following relationship: 1.84≤nd4≤2.01, and / or, 19≤vd4≤40.

5. The optical system according to claim 1, wherein The refractive index of the third lens is nd3, and the Abbe number is vd3, which satisfies the following relationship: 1.6≤nd3≤1.75, and / or, 19≤vd3≤25.

6. The optical system according to claim 1, wherein The refractive index of the second lens, the fifth lens, and the seventh lens are all nd257, and the Abbe number of the second lens, the fifth lens, and the seventh lens are all vd257, satisfying the following relationship: 1.45≤nd257≤1.6, and / or, 50≤vd257≤60.

7. The optical system according to claim 1, wherein The focal length of the first lens is φ1, -19<φ1<-15mm; and / or, The focal length of the second lens is φ2, -3.5<φ2<-6mm; and / or, The focal length of the third lens is φ3, -14<φ3<-10mm; and / or, The focal length of the fourth lens is φ4, 3<φ4<6mm; and / or, The focal length of the fifth lens is φ5, 1<φ5<5mm; and / or, The focal length of the sixth lens is φ6, -1<φ6<-5mm; and / or, The focal length of the seventh lens is φ7, 2<φ7<6mm.

8. A video optical lens, characterized in that: include: A lens barrel extends along the optical axis, wherein a cavity extending along the optical axis is formed in the lens barrel; as well as, The optical system according to any one of claims 1 to 7, wherein the optical system is arranged in the cavity.

9. A video conferencing device, characterized in that: The invention comprises the video optical lens as claimed in claim 8.

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