CN116908999A - Large wide-angle low-distortion video conference lens - Google Patents
Large wide-angle low-distortion video conference lens Download PDFInfo
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
- G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
- G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
- G02B13/0045—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
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Abstract
A wide-angle low-distortion lens sequentially comprises, from an object side to an image side: a first lens having negative optical power, a second lens having negative optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power. The first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses. Wherein the horizontal half field angle of the wide-angle low-distortion lens is HFOV, and the total optical length of the wide-angle low-distortion lens is TTL, which satisfies the following relation:the method comprises the steps of carrying out a first treatment on the surface of the Thereby achieving wide-angle image capturing performance. The optical power of the lens group and the optical power composing each lens group are reasonably distributed in the distortion control, the special problem of optical distortion is solved, and the system optics is realized on the premise of reaching high pixelsThe distortion is less than 5%.
Description
Technical Field
The application relates to the field of cameras, in particular to a wide-angle low-distortion glass-plastic mixed lens structure.
Background
Video shots are a special optical device used to meet application requirements in remote video communications and conferencing. The video conference lens is characterized in that image acquisition and imaging can be performed to meet various requirements on image quality, definition, stability and the like in the conference process. The video conference lens has the characteristics of high precision, high definition and the like, can provide clear and stable video images in the conference process, and creates more realistic communication scenes. The coverage range is still another big characteristic of video conference lenses, the view angle ranges of the lenses with different specifications and models are also different, and in general, the video conference lenses have wide view angles, so that more comprehensive scene display can be realized in a conference. The video conference lens has the functions of automatic focusing and the like, can flexibly change shooting angles and focuses according to conference requirements, and better meets the actual requirements under various complex scenes.
With more and more co-operation across regions, video conferencing lenses have become an integral part of modern productivity. The video conference lens can provide clear, smooth, stable and reliable video service and meet the requirements of various online video conferences. In recent years, network education has been rapidly developed, and education methods of this type mainly transmit teaching contents to students through a network or other forms of electronic media, so that educational resources can be distributed more fairly to everyone. In short, the video conference lens is used as a key device for realizing application scenes such as teleconference, education and the like, and has an irreplaceable function in meeting the requirements of users on definition, stability and the like. In addition, with the continuous development of the intelligent technology, the video conference lens tends to be more intelligent, and has more abundant and diversified functions.
The existing video conference lens has low pixels, the horizontal view angle is generally about 70 degrees, and the wide-angle image capturing is limited; in addition, the ten glass lenses used in the lens described in chinese patent No. CN104076490a and the lens described in chinese patent No. CN106125260a are seven glass lenses and the lens described in chinese patent No. CN206505216U are seven lenses, which is not only disadvantageous for miniaturization but also increases the manufacturing cost.
The application provides a video conference lens, which provides a wide-angle low-distortion video lens with a view angle of 100 degrees, a large aperture and high pixels, and can be used for solving the technical problems.
Disclosure of Invention
In order to solve the problems that the optical total length of the video conference lens is too long, the aberration balance capability is limited, the imaging quality requirement is difficult to meet, and the like. The application provides a glass-plastic mixed lens structure with large wide angle and low distortion.
In order to achieve the above purpose, the technical scheme provided by the application is as follows:
a large wide-angle low-distortion video conference lens having six lenses with refractive power, the video conference lens comprising 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, a fifth lens with negative optical power, and a sixth lens with positive optical power, which are arranged in order from an object side to an image side along an optical axis;
the first lens element with negative refractive power has a planar object-side surface at a paraxial region and a concave image-side surface at the paraxial region;
the second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the fourth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the fifth lens element with negative refractive power has a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region;
the sixth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the video conference lens further comprises a seventh lens, wherein the seventh lens is a protective glass;
a diaphragm is arranged between the third lens and the fourth lens;
the horizontal angle of view of the large-wide-angle low-distortion video conference lens is HFOV, and the total optical length of the large-wide-angle low-distortion video conference lens is TTL, which satisfies the following relation:。
further, the maximum chief ray angle of the large wide angle low distortion video conference lens is CRA, which satisfies the relation: CRA <20 °.
Further, the effective focal length of the large-wide-angle low-distortion video conference lens is f, and the entrance pupil diameter of the large-wide-angle low-distortion video conference lens is D, which satisfies the relation: 1.8< f/D <2.
Further, the refractive index of the material of the fourth lens is nd4, the abbe number of the material of the fourth lens is vd4, the refractive index of the material of the fifth lens is nd5, the abbe number of the material of the fifth lens is vd5, the refractive index of the material of the sixth lens is nd6, and the abbe number of the material of the sixth lens is vd6, which satisfies the relation: 1.5< nd4<1.55, vd4>50, 1.6< nd5<1.65, vd5<30, 1.5< nd6<1.55, vd6>50.
Further, the half field angle of the large wide angle low distortion video conference lens is w, and the formula is satisfied: 2 w=100°.
Further, the total optical length TTL of the large-wide-angle low-distortion video conference lens is 20mm.
Further, the distortion range of the large-wide-angle low-distortion video conference lens is-5% -1%.
Further, the first lens and the third lens of the large-wide-angle low-distortion video conference lens are glass spherical lenses, the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspheric lenses, and the seventh lens is protective glass.
Further, the optical total length of the large-wide-angle low-distortion video conference lens is TTL, and the effective focal length of the large-wide-angle low-distortion video conference lens is f, which satisfies the relation: 5< TTL/f <5.5.
Compared with the prior art, the application has the beneficial effects that:
the application relates to a wide-angle low-distortion video conference lens, which adopts a six-piece structure; the method sequentially comprises the following steps from an object side to an image side: a first lens having negative optical power, a second lens having negative optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power. When the incident light passes through the first lens with negative refractive power, the light with a larger field of view can be effectively coupled into the optical lens, and the object side surface and the image side surface of the first lens are respectively plane and concave surface designs at the paraxial region, so that the angle of view of the optical lens can be increased, and the total optical length of the optical lens can be shortened. The second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, which is conducive to controlling a chief ray angle of the optical lens element, reducing reflection of light rays on a surface of the lens element, and correcting aberrations. The third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, so that the refractive power of the optical lens element is reasonably distributed, the movement range of the refractive power of the optical lens element in the object-side direction is reduced, the total optical length of the optical lens element is reduced, and the miniaturization design requirement is met. The fourth lens, the fifth lens and the sixth lens are in positive, negative and positive structures, and the structures can well balance various aberrations in the system. The optical power of the lens groups and the optical power of the lens groups are reasonably distributed in distortion control, so that the special problem of optical distortion is solved, and the optical distortion of the system is less than 5% on the premise of reaching high pixels.
The application relates to a wide-angle low-distortion video conference lens, which adopts 2 glass spherical lenses and 4 aspheric plastic lenses, is beneficial to increasing the angle of view of an optical lens, shortens the total optical length of the optical lens, and meets the design requirement of miniaturization. The fourth lens, the fifth lens and the sixth lens are in positive, negative and positive structures, and the structures can well balance various aberrations in the system. The optical power of the lens groups and the optical power of the lens groups are reasonably distributed in distortion control, so that the special problem of optical distortion is solved, and the optical distortion of the system is less than 5% on the premise of reaching high pixels. The parameters achieved by the patent of the application are as follows: the focal length of the system is smaller than 4mm, the F number is 1.8-2.0, the total length of the system is smaller than 20mm, the full view angle of the system reaches 100 degrees, and the MTF of the system can reach 0.3 at 180 lp/mm.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural view of an optical lens disclosed in a first embodiment of the present application.
Fig. 2 is a Modulation Transfer Function (MTF) resolution diagram disclosed in the first embodiment of the present application.
Fig. 3 is a full field RMS spot size disclosed in the first embodiment of the application.
Fig. 4 is a distortion chart disclosed in the first embodiment of the present application.
Fig. 5 is a longitudinal color difference chart disclosed in the first embodiment of the present application.
Fig. 6 is a lateral color chart of the disclosure of the first embodiment of the present application.
Fig. 7 is a schematic structural diagram of an optical lens according to a second embodiment of the present application.
Fig. 8 is a Modulation Transfer Function (MTF) resolution diagram disclosed in the second embodiment of the present application.
Fig. 9 is a full field RMS spot size disclosed in the second embodiment of the application.
Fig. 10 is a distortion chart disclosed in the second embodiment of the present application.
Fig. 11 is a longitudinal color difference chart disclosed in the second embodiment of the present application.
Fig. 12 is a lateral color chart of the disclosure of the second embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the present application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate an azimuth or a positional relationship based on that shown in the drawings. These terms are only used to better describe the present application and its embodiments and are not intended to limit the scope of the indicated devices, elements or components to the particular orientations or to configure and operate in the particular orientations.
Also, some of the terms described above may be used to indicate other meanings in addition to orientation or positional relationships, for example, the term "upper" may also be used to indicate some sort of attachment or connection in some cases. The specific meaning of these terms in the present application will be understood by those of ordinary skill in the art according to the specific circumstances.
Furthermore, the terms "first," "second," and the like, are used primarily to distinguish between different devices, elements, or components (the particular species and configurations may be the same or different), and are not used to indicate or imply the relative importance and number of devices, elements, or components indicated. Unless otherwise indicated, the meaning of "a plurality" is two or more.
As shown in fig. 1, the large wide-angle low-distortion video conference lens system of the present application includes, in order from left to right, a first lens element L1, a second lens element L2, a third lens element L3, a stop, a fourth lens element L4, a fifth lens element L5, a sixth lens element L6, and a seventh lens element L7, wherein S1 is an object side surface of the first lens element L1, S2 is an image side surface of the first lens element L1, S3 is an object side surface of the second lens element L2, S4 is an image side surface of the second lens element L2, S5 is an object side surface of the third lens element L3, S6 is an image side surface of the third lens element L3, S7 is an object side surface of the fourth lens element L4, S8 is an image side surface of the fourth lens element L4, S9 is an object side surface of the fifth lens element L5, S10 is an image side surface of the fifth lens element L5, S11 is an object side surface of the sixth lens element L6, S13 is an object side surface of the seventh lens element L7, S14 is an image side surface of the third lens element L4, and the third lens element L4 is a virtual line.
Further, the first lens element with negative refractive power has an object-side surface being planar at a paraxial region and an image-side surface being concave at the paraxial region; the second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; the third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; the fourth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region; the fifth lens element with negative refractive power has a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the sixth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region; the seventh lens is a protective glass; and a diaphragm is arranged between the third lens and the fourth lens.
The horizontal angle of view of the wide-angle low-distortion lens is HFOV, and the total optical length of the wide-angle low-distortion lens is TTL, which satisfies the relationship:when the optical lens satisfies the above relation, the optical total length of the optical lens can be ensured to be kept within a reasonable range, the length of the optical lens is reduced, the miniaturization requirement of the optical lens is satisfied, and meanwhile, the design of large view field is satisfied, so that the optical lens can observe a large enough range, and a wide angle is realizedAnd the image capturing performance is improved, and the service performance of the lens is improved, so that the wide-angle image capturing performance is realized.
The optical lens satisfies the following relation:
5＜TTL/f＜5.5；
wherein TTL is the distance from the object side surface of the first lens to the imaging surface of the optical lens on the optical axis (i.e. the total optical length of the optical lens), and f is the focal length of the optical lens. When the optical lens satisfies 5< TTL/f <5.5, the optical lens has a larger depth of field while the miniaturized design is realized by limiting the relation between the total optical length and the focal length of the optical lens. That is, when the optical lens satisfies the above relation, the focal length of the optical lens can be made smaller, which can obtain a larger depth of field.
The maximum chief ray angle of the wide angle low distortion lens is CRA, which satisfies the relation: CRA <20 degrees, so the CCD-type LED light source can be compatible with multiple COMS/CCDs, has wide application prospect and improves market competitiveness.
The effective focal length of the wide-angle low-distortion lens is f, and the entrance pupil diameter of the wide-angle low-distortion lens is D, which satisfies the relation: 1.8< f/D <2. Therefore, the aperture stop belongs to a large aperture optical system and can meet the aperture stop use requirement of F1.8-2.0.
The refractive index of the material of the fourth lens is nd4, the abbe number of the material of the fourth lens is vd4, the refractive index of the material of the fifth lens is nd5, the abbe number of the material of the fifth lens is vd5, the refractive index of the material of the sixth lens is nd6, and the abbe number of the material of the sixth lens is vd6, which satisfies the relation: 1.5< nd4<1.55, vd4>50, 1.6< nd5<1.65, vd5<30, 1.5< nd6<1.55, vd6>50, and reasonable materials are selected, and the high-low dispersion coefficients of the fourth lens, the fifth lens and the sixth lens are matched with each other, so that system chromatic aberration can be effectively corrected, a high-resolution color image is provided, and imaging effect is guaranteed.
The half field angle of the wide-angle low-distortion lens structure is w, and the following formula is satisfied: 2 w=100°.
The total optical length TTL of the wide-angle low-distortion lens structure is 20mm.
The structural distortion range of the wide-angle low-distortion lens is-5% -1%.
The first lens and the third lens of the wide-angle low-distortion lens structure are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspheric lenses; the application adopts the combination of glass material and plastic aspheric surface material, which is beneficial to shortening the total optical length.
The wide-angle low-distortion lens sequentially comprises, from an object side to an image side: a first lens having negative optical power, a second lens having negative optical power, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power. The first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses. The aspherical surface shape is determined by the following formula:
let the z-axis be the optical axis, the origin of the rectangular coordinate system (x, y, z) coincides with the origin of the aspheric surface, and the rotational axis coincides with the optical axis of the system, the shape of the aspheric surface can be expressed as:
wherein, the liquid crystal display device comprises a liquid crystal display device,the height of incidence of a ray on an aspherical surface, k is the conic coefficient, A2, A4, A6. z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis O direction; c is the curvature at the optical axis O, c=1/R (i.e., paraxial curvature c is the inverse of the radius of curvature R in table 1); k is a conical surface coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. The following table 2 gives the higher order coefficients A4, A6, A8, a10, a12 that can be used for each aspherical mirror in the first embodiment.
The optical lens satisfies the following relation:
the method comprises the steps of carrying out a first treatment on the surface of the For example, a->May be 0.051 mm, 0.052 mm, 0.053 mm, 0.054 mm, 0.055 mm, 0.056 mm, 0.057 mm, 0.058 mm, 0.059mm, etc. Wherein TTL is the distance between the object side surface of the first lens and the imaging surface of the optical lens on the optical axis O, and HFOV is the horizontal half field angle of the wide-angle low-distortion lens. When the optical lens satisfies->When the optical lens is used, the optical total length of the optical lens can be kept in a reasonable range, so that the length of the optical lens is shortened, the optical total length of the optical lens can be kept in a reasonable range, the length of the optical lens is shortened, the design of a large view field can be met while the miniaturization requirement of the optical lens is met, the optical lens can observe a large enough range, the wide-angle image capturing performance is realized, the service performance of the lens is improved, and the wide-angle image capturing performance is realized. The optical lens satisfying the above relation can also avoid the overlarge diameter of the first lens L1 caused by overlarge field angle, thereby ensuring that the diameter of the optical lens is kept within a reasonable range, and also reducing the size of the lens. By reasonably configuring the relation between the total optical length of the optical lens and the maximum field angle of the optical lens, the design of meeting the requirement of miniaturization of the optical lens and meeting a large field of view is realized.
Example 1
The application relates to a wide-angle low-distortion video conference lens, which adopts a six-piece structure, as shown in fig. 1, and comprises the following components in sequence from object measurement to image side: a first lens L1 having negative optical power, a second lens L2 having negative optical power, a third lens L3 having negative optical power, a fourth lens L4 having positive optical power, a fifth lens L5 having negative optical power, and a sixth lens L6 having positive optical power.
When the incident light passes through the first lens with negative refractive power, the light with a larger field of view can be effectively coupled into the optical lens, and the object side surface and the image side surface of the first lens are respectively plane and concave surface designs at the paraxial region, so that the angle of view of the optical lens can be increased, and the total optical length of the optical lens can be shortened. The second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, which is conducive to controlling a chief ray angle of the optical lens element, reducing reflection of light rays on a surface of the lens element, and correcting aberrations. The third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, so that the refractive power of the optical lens element is reasonably distributed, the movement range of the refractive power of the optical lens element in the object-side direction is reduced, the total optical length of the optical lens element is reduced, and the miniaturization design requirement is met. The fourth lens, the fifth lens and the sixth lens are in positive, negative and positive structures, and the structures can well balance various aberrations in the system. The optical power of the lens groups and the optical power of the lens groups are reasonably distributed in distortion control, so that the special problem of optical distortion is solved, and the optical distortion of the system is less than 5% on the premise of reaching high pixels.
Specifically, in the present embodiment, the optical parameters of the large wide-angle low-distortion video conference lens are shown in table 1-1 and table 1-2, the effective focal length of the wide-angle low-distortion video conference lens is f=4mm, the aperture f# is 2.0, the angle of view is 100 °, the total length of the system is 20mm, and the large wide-angle low-distortion video conference lens can be matched with a 1/2.7″ photo-sensitive chip.
The basic optical parameters of the large wide angle low distortion video conference lens of this embodiment are shown in tables 1-1 and 1-2 below,
TABLE 1-1
TABLE 1-2
Detailed optical data of the large wide-angle low-distortion video conference lens in this embodiment are shown in tables 1 to 3 and tables 1 to 4 below,
tables 1 to 3
Tables 1 to 4
Wherein, let z axis be the optical axis, the origin (x, y, z) of rectangular coordinate system coincides with the origin of the aspheric surface, and the rotation axis coincides with the optical axis of the system, the surface shape of the aspheric surface can be expressed as:
wherein, the liquid crystal display device comprises a liquid crystal display device,the height of incidence of a ray on an aspherical surface, k is the conic coefficient, A2, A4, A6. z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis O direction; c is the curvature at the optical axis O, c=1/R (i.e., paraxial curvature c is the inverse of the radius of curvature R in table 1); k is a conical surface coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Tables 1-4 show the higher order coefficients A4, A6, A8, A10, A12 that can be used for each of the aspherical mirrors in the first embodiment.
In the above table, f is the focal length of the optical system, and f1 to f6 are the focal lengths of the respective lenses in order.
Fig. 2 to 6 are a Modulation Transfer Function (MTF) analysis chart, a full-field RMS spot size, a distortion chart, a longitudinal chromatic aberration chart, and a lateral chromatic aberration chart in this order. As can be seen from the graph, when the system modulation function (MTF) is 180lp/mm, the central field Modulation Transfer Function (MTF) >0.6 and the maximum field Modulation Transfer Function (MTF) >0.3 meet the requirement of high pixels, and meanwhile, the system distortion is controlled within-5%.
Therefore, the wide-angle low-distortion lens provided by the first embodiment of the application can meet the requirements of low distortion and high resolution of the system.
Example two
The application relates to a wide-angle low-distortion video conference lens, which adopts a six-piece structure, as shown in fig. 7, and is similar to fig. 1 corresponding to the first embodiment, and comprises the following components from object measurement to image side in sequence: a first lens L8 having negative optical power, a second lens L9 having negative optical power, a third lens L10 having negative optical power, a fourth lens L11 having positive optical power, a fifth lens L12 having negative optical power, and a sixth lens L13 having positive optical power.
When the incident light passes through the first lens with negative refractive power, the light with a larger field of view can be effectively coupled into the optical lens, and the object side surface and the image side surface of the first lens are respectively plane and concave surface designs at the paraxial region, so that the angle of view of the optical lens can be increased, and the total optical length of the optical lens can be shortened. The second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, which is conducive to controlling a chief ray angle of the optical lens element, reducing reflection of light rays on a surface of the lens element, and correcting aberrations. The third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region, so that the refractive power of the optical lens element is reasonably distributed, the movement range of the refractive power of the optical lens element in the object-side direction is reduced, the total optical length of the optical lens element is reduced, and the miniaturization design requirement is met. The fourth lens, the fifth lens and the sixth lens are in positive, negative and positive structures, and the structures can well balance various aberrations in the system. The optical power of the lens groups and the optical power of the lens groups are reasonably distributed in distortion control, so that the special problem of optical distortion is solved, and the optical distortion of the system is less than 5% on the premise of reaching high pixels.
In the second embodiment, the aperture is increased to 1.8 compared with the embodiment 1, the effective focal length is shortened to 3.6mm, the performance index is better, and the effect is better.
Specifically, in the present embodiment, the optical parameters of the large wide-angle low-distortion video conference lens are shown in table 2-1 and table 2-2, the effective focal length of the wide-angle low-distortion video conference lens is f=3.6 mm, the aperture f# is 1.8, the angle of view is 100 °, the total length of the system is 20mm, and the large wide-angle low-distortion video conference lens can be matched with a 1/2.7″ photo-sensitive chip.
The basic optical parameters of the large wide angle low distortion video conference lens of this embodiment are shown in tables 2-1 and 2-2 below,
TABLE 2-1
TABLE 2-2
Detailed optical data of the large wide angle low distortion video conference lens of this embodiment are shown in tables 2-3 and tables 2-4 below,
tables 2 to 3
Tables 2 to 4
Wherein, let z axis be the optical axis, the origin (x, y, z) of rectangular coordinate system coincides with the origin of the aspheric surface, and the rotation axis coincides with the optical axis of the system, the surface shape of the aspheric surface can be expressed as:
wherein, the liquid crystal display device comprises a liquid crystal display device,the height of incidence of light on an aspherical surface, k is a conic coefficient, A2, A4, A6Curvature at the apex. z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis O direction; c is the curvature at the optical axis O, c=1/R (i.e., paraxial curvature c is the inverse of the radius of curvature R in table 1); k is a conical surface coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Tables 2-4 show the higher order coefficients A4, A6, A8, A10, A12 that can be used for each of the aspherical mirrors in the second embodiment.
In the above table, f is the focal length of the optical system, and f8 to f13 are the focal lengths of the respective lenses in order.
Fig. 8 to 12 are a Modulation Transfer Function (MTF) analysis chart, a full-field RMS spot size, a distortion chart, a longitudinal chromatic aberration chart, and a lateral chromatic aberration chart in this order. As can be seen from the graph, when the system modulation function (MTF) is 180lp/mm, the central field Modulation Transfer Function (MTF) >0.5 and the maximum field Modulation Transfer Function (MTF) >0.4 meet the requirement of high pixels, and meanwhile, the system distortion is controlled within-5%.
Therefore, the wide-angle low-distortion lens provided by the second embodiment of the application can meet the requirements of low distortion and high resolution of the system.
The application solves the problems of small full field angle and low pixels in the prior art, and can realize wide-angle image capture with the field angle of 100 degrees. The application adopts two glass spherical lenses and four plastic aspherical lenses, which not only reduces the weight of the lens, but also realizes the effects of wide angle, low distortion, large aperture and high pixel, and can well correct on-axis and off-axis aberration, has excellent optical performance, and can meet the application requirements of different clients.
Claims (9)
1. A large wide-angle low-distortion video conference lens, characterized in that the video conference lens has six lenses with refractive power in total, and the video conference lens comprises 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, a fifth lens with negative optical power and a sixth lens with positive optical power, which are sequentially arranged from an object side to an image side along an optical axis;
the first lens element with negative refractive power has a planar object-side surface at a paraxial region and a concave image-side surface at the paraxial region;
the second lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the third lens element with negative refractive power has a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the fourth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the fifth lens element with negative refractive power has a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region;
the sixth lens element with positive refractive power has a convex object-side surface at a paraxial region and a convex image-side surface at a paraxial region;
the video conference lens further comprises a seventh lens, wherein the seventh lens is a protective glass;
a diaphragm is arranged between the third lens and the fourth lens;
the horizontal angle of view of the large-wide-angle low-distortion video conference lens is HFOV, and the total optical length of the large-wide-angle low-distortion video conference lens is TTL, which satisfies the following relation:。
2. the large wide-angle low-distortion video conferencing lens of claim 1, wherein the large wide-angle low-distortion video conferencing lens has a maximum chief ray angle CRA that satisfies the relationship: CRA <20 °.
3. The large wide-angle low-distortion video conference lens of claim 1, wherein the effective focal length of the large wide-angle low-distortion video conference lens is f, and the entrance pupil diameter of the large wide-angle low-distortion video conference lens is D, which satisfies the relationship: 1.8< f/D <2.
4. The large wide-angle low-distortion video conference lens according to claim 1, wherein the material refractive index of the fourth lens is nd4, the material abbe number of the fourth lens is vd4, the material refractive index of the fifth lens is nd5, the material abbe number of the fifth lens is vd5, the material refractive index of the sixth lens is nd6, and the material abbe number of the sixth lens is vd6, which satisfies the relation: 1.5< nd4<1.55, vd4>50, 1.6< nd5<1.65, vd5<30, 1.5< nd6<1.55, vd6>50.
5. The large wide-angle low-distortion video conference lens of claim 1, wherein the large wide-angle low-distortion video conference lens half field angle is w, satisfying the formula: 2 w=100°.
6. The large wide-angle low distortion video conferencing lens of claim 1, wherein the large wide-angle low distortion video conferencing lens has an optical total length TTL of 20mm.
7. The large wide-angle low-distortion video conference lens of claim 1, wherein the large wide-angle low-distortion video conference lens distortion range is-5% -1%.
8. The large wide-angle low-distortion video conference lens of claim 1, wherein the first lens and the third lens of the large wide-angle low-distortion video conference lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses.
9. The large wide-angle low distortion video conferencing lens of claim 1, wherein the large wide-angle low distortion video conferencing lens has an optical total length TTL and an effective focal length f that satisfies the relationship: 5< TTL/f <5.5.
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| CN116908999B (en) | 2023-12-08 |
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