A lens

Abstract

The invention discloses a lens, comprising: a first lens group, a second lens group, a third lens group, a fourth lens group, a spectroscopic device, a filtering device and an identification device, wherein the first lens group, the second lens group, the third lens group, the fourth lens group, the spectroscopic device, the filtering device and the identification device are sequentially arranged between the object side and the imaging side; the inlet of the spectroscopic device is connected with the outlet of the fourth lens group, and the outlet of the spectroscopic device is connected with the inlet of the filtering device, so as to separate the light beam at the outlet of the fourth lens group into a horizontal light beam and a vertical light beam, and independently send the horizontal light beam and the vertical light beam to the filtering device; the filtering device is used to receive the horizontal light beam and the vertical light beam, filter the horizontal light beam and the vertical light beam, and independently send the filtered horizontal light beam and the vertical light beam to the identification device; the identification device is used to receive and identify the filtered horizontal light beam and the vertical light beam.

Description

Technical Field

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

[0002] With the development of society, people's awareness of safety precautions has been continuously improved, the security monitoring industry has also been rapidly developed, and the role of monitoring has become increasingly important. Zoom lenses have been actually designed and used in the last century. With the development of lens design technology, the application occasions of zoom lenses have gradually increased. Nowadays, zoom lenses have been widely used in civilian products, security monitoring and other fields. For example, high-pixel, wide-band, and large-aperture 3D recognition lenses are mostly used in vehicle-mounted, machine vision, public safety, monitoring and other fields. In public safety recognition, most of them use dual-lens mode, using dual CMOS (Complementary Metal Oxide Semiconductor) to respectively identify visible light and infrared light, but dual lenses involve software splicing and complex algorithm processing, and the structure is complex and the cost is expensive, which is not conducive to improving market competitiveness. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] To this end, the present invention proposes a lens that can perform separate identification of visible light and infrared light, has a simple structure, and is conducive to reducing costs.

[0005] A lens according to an embodiment of the present invention comprises: a first lens group, a second lens group, a third lens group, a fourth lens group, a light splitting device, a light filtering device and a recognition device, wherein the first lens group, the second lens group, the third lens group, the fourth lens group, the light splitting device, the light filtering device and the recognition device are sequentially arranged between the object side and the imaging side; the light splitting device is arranged between the fourth lens group and the light filtering device, the inlet of the light splitting device is connected with the outlet of the fourth lens group, and the outlet of the light splitting device is connected with the inlet of the light filtering device, and is used to split the light beam at the outlet of the fourth lens group into a horizontal light beam and a vertical light beam, and independently send the horizontal light beam and the vertical light beam to the light filtering device;

[0006] The filtering device is arranged between the light splitting device and the recognition device, and is used to receive the horizontal light beam and the vertical light beam, filter the horizontal light beam and the vertical light beam, and independently send the filtered horizontal light beam and the vertical light beam to the recognition device;

[0007] The identification device is used to receive and identify the filtered horizontal light beam and vertical light beam.

[0008] A lens according to an embodiment of the present invention has at least the following beneficial effects: multiple lens groups are used to reduce aberrations and improve image quality; a light beam passing through multiple lens groups is separated into a horizontal light beam and a vertical light beam by a light splitting device, and the horizontal light beam and the vertical light beam are independently sent to a filtering device for filtering processing; the filtering device independently sends the filtered horizontal light beam and the vertical light beam to a recognition device for separate recognition and imaging; the lens in the above technical solution can perform separate recognition of visible light and infrared light, and has the function of a dual lens, has a simple structure, and is conducive to reducing costs.

[0009] According to some embodiments of the present invention, the first lens group includes a first lens and a second lens; wherein the first lens and the second lens are both negative optical power lenses, the shapes of the first lens and the second lens are both crescent-shaped, the convex side of the first lens faces the object side, and the concave side of the first lens faces the convex side of the second lens.

[0010] According to some embodiments of the present invention, the first lens satisfies the following conditions: -44<f(100)<-25; 1.7<D1 / R2<1.82; 1.7<Nd1<1.8; wherein f(100) is the focal length of the first lens, Nd1 is the refractive index of the first lens, D1 is the diameter of the concave side of the first lens, and R2 is the curvature radius of the concave side of the first lens.

[0011] According to some embodiments of the present invention, the second lens group includes a third lens and a fourth lens; wherein the edges of the third lens and the fourth lens are glued to form a negative optical focal length lens, the third lens is in a crescent shape, the fourth lens is a double concave lens, the concave side of the third lens faces the concave side of the second lens, the convex side of the third lens faces the fourth lens, and the curvature radius of the concave side of the fourth lens facing the third lens is the same as the curvature radius of the convex side of the third lens.

[0012] According to some embodiments of the present invention, the third lens group includes a fifth lens and a sixth lens; wherein the fifth lens and the sixth lens are both biconvex lenses and both are positive optical power lenses, and the fifth lens is arranged between the fourth lens and the sixth lens.

[0013] According to some embodiments of the present invention, the fifth lens and the sixth lens satisfy the following condition: 1.1<|f(500) / f(600)|<2.2; wherein f(500) is the focal length of the fifth lens, and f(600) is the focal length of the sixth lens.

[0014] According to some embodiments of the present invention, the fourth lens group includes a seventh lens and an eighth lens; wherein the edges of the seventh lens and the eighth lens are glued to form a positive optical power lens, the seventh lens is a meniscus lens, the eighth lens is a double convex lens, the convex side of the seventh lens faces the sixth lens, the concave side of the seventh lens faces the convex side of the eighth lens, and the curvature radius of the concave side of the seventh lens is the same as the curvature radius of the convex side of the eighth lens.

[0015] According to some embodiments of the present invention, the third lens, the sixth lens and the seventh lens satisfy the following condition: 2.6<|R 31 / R 61 +R 71 ∣<4; where R 31 is the radius of curvature of the concave surface of the third lens, R 61 is the radius of curvature of the sixth lens facing the fifth lens, R 71 is the radius of curvature of the convex surface of the seventh lens.

[0016] According to some embodiments of the present invention, the first lens and the seventh lens satisfy the following conditions: R 12 >R 72 ; Among them, R 12 is the radius of curvature of the concave surface of the first lens, R 72 is the curvature radius of the concave surface of the seventh lens.

[0017] According to some embodiments of the present invention, the fourth lens group further includes a ninth lens and a tenth lens; wherein the edges of the ninth lens and the tenth lens are glued to form a negative optical focal length lens, the ninth lens is a double concave lens, the tenth lens is a double convex lens, and the curvature radius of the concave side of the ninth lens facing the tenth lens is the same as the curvature radius of the convex side of the tenth lens facing the ninth lens.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 is a schematic structural diagram of a lens according to an embodiment of the present invention;

[0021] Figure 2 A path diagram of a light beam passing through a lens according to an embodiment of the present invention;

[0022] Figure 3 is a schematic structural diagram of a lens according to another embodiment of the present invention;

[0023] Figure 4 A path diagram of a light beam passing through a lens according to another embodiment of the present invention;

[0024] Figure 5 A transfer function (MTF) curve diagram of the lens provided in an embodiment of the present invention at 400-700nm;

[0025] Figure 6 The mobile transfer function (MTF) curve of the lens provided in the embodiment of the present invention at 800-1000nm.

[0026] Reference numerals:

[0027] A first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a first lens 100, a second lens 200, a third lens 300, a fourth lens 400, a fifth lens 500, a sixth lens 600, a seventh lens 700, an eighth lens 800, a ninth lens 900, a tenth lens 110, an eleventh lens 120, a twelfth lens 130, a spectrometer 140, a filter 150, a first filter 1501, a second filter 1502, an identification device 160, a first chip 1601, a second chip 1602, a first protective window 1603, and a second protective window 1604 DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should be understood that, with respect to descriptions of orientation, the orientations or positional relationships indicated by terms such as “center, longitudinal, transverse, length, width, thickness, up, down, front, back, left, right, vertical, horizontal, top, bottom, inside, outside, circumferential, radial, circumferential”, etc. are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0030] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Reference below Figure 1 and Figure 3 A lens according to an embodiment of the present invention is described.

[0033] like Figure 1 and Figure 3 As shown, a lens according to an embodiment of the present invention includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens G4, a spectrometer 140, a filter 150 and a recognition device 160, and the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens G4, the spectrometer 140, the filter 150 and the recognition device 160 are sequentially arranged between the object side and the imaging side.

[0034] Specifically, the light splitting device 140 is disposed between the fourth lens group G4 and the filter device 150, the inlet of the light splitting device 140 is connected to the outlet of the fourth lens group G4, and the outlet of the light splitting device 140 is connected to the inlet of the filter device 150. Figure 2 and Figure 4 As shown, the light splitting device 140 is used to split the light beam at the exit of the fourth lens group G4 into a horizontal light beam and a vertical light beam, and independently send the horizontal light beam and the vertical light beam to the filter device 150. The filter device 150 is arranged between the light splitting device 140 and the recognition device 160, and the filter device 150 is used to receive the horizontal light beam and the vertical light beam, filter the horizontal light beam and the vertical light beam, and independently send the filtered horizontal light beam and the vertical light beam to the recognition device 160. The recognition device 160 is used to receive and recognize the filtered horizontal light beam and the vertical light beam, and image the light beams.

[0035] The use of multiple lens groups is beneficial to reducing aberrations and improving image quality; the light beams passing through the multiple lens groups are separated into horizontal light beams and vertical light beams by the light splitting device 140, and the horizontal light beams and the vertical light beams are independently sent to the filtering device 150 for filtering processing; the filtering device 150 independently sends the filtered horizontal light beams and vertical light beams to the recognition device 160 for separate recognition and imaging; the lens in the above technical solution can be used to separately recognize visible light and infrared light, and at the same time has the function of dual lenses, with a simple structure, which is conducive to reducing costs.

[0036] In some specific embodiments of the present invention, the first lens group G1 includes a first lens 100 and a second lens 200. The first lens 100 and the second lens 200 are both negative power lenses. The shapes of the first lens 100 and the second lens 200 are both crescent-shaped. The convex side of the first lens 100 faces the object side, and the concave side of the first lens 100 faces the convex side of the second lens 200.

[0037] Further, the first lens satisfies the following conditions: -44<f(100)<-25; 1.7<D1 / R2<1.82;

[0038] 1.7<Nd1<1.8; wherein, f(100) is the focal length of the first lens 100, Nd1 is the refractive index of the first lens 100, D1 is the diameter of the concave side of the first lens (100), that is, the diameter of the meniscus of the first lens (100) (the effective aperture on the right side of the lens), and R2 is the radius of curvature of the concave side of the first lens (100).

[0039] In some specific embodiments of the present invention, the second lens group G2 includes a third lens 300 and a fourth lens 400, the edges of the third lens 300 and the fourth lens 400 are glued to form a negative power lens, the shape of the third lens 300 is a crescent shape, the fourth lens 400 is a double concave lens, the concave side of the third lens 300 faces the concave side of the second lens 200, the convex side of the third lens 300 faces the fourth lens 400, and the curvature radius of the concave side of the fourth lens 400 facing the third lens 300 is the same as the curvature radius of the convex side of the third lens 300.

[0040] In some specific embodiments of the present invention, the third lens group G3 includes a fifth lens 500 and a sixth lens 600 ; the fifth lens 500 and the sixth lens 600 are both biconvex lenses and both are positive power lenses, and the fifth lens 500 is disposed between the fourth lens 400 and the sixth lens 600 .

[0041] Further, the fifth lens 500 and the sixth lens 600 satisfy the following condition: 1.1<|f(500) / f(600)|<2.2; wherein f(500) is the focal length of the fifth lens 500 , and f(600) is the focal length of the sixth lens 600 .

[0042] Further, the Abbe number Abbe of the fifth lens 500 satisfies 30<ABBE<40.

[0043] In some specific embodiments of the present invention, the fourth lens group G4 includes a seventh lens 700 and an eighth lens 800; the seventh lens 700 is a negative power lens, the eighth lens 800 is a positive power lens, the edges of the seventh lens 700 and the eighth lens 800 are glued to form a positive power lens, the seventh lens 700 is a meniscus lens (convex on the left and concave on the right), the eighth lens 800 is a double convex lens, the convex side of the seventh lens 700 faces the sixth lens 600, the concave side of the seventh lens 700 faces the convex side of the eighth lens 800, and the curvature radius of the concave side of the seventh lens 700 is the same as the curvature radius of the convex side of the eighth lens 800.

[0044] Furthermore, the third lens 300, the sixth lens 600 and the seventh lens 700 satisfy the following condition: 2.6<|R 31 / R 61 +R 71 ∣<4; where R 31 is the curvature radius of the concave surface of the third lens 300, R 61 is the curvature radius of the sixth lens 600 facing the fifth lens 500, R 71 is the radius of curvature of the convex surface of the seventh lens 700.

[0045] Furthermore, the first lens 100 and the seventh lens 700 satisfy the following conditions: R 12 >R 72 ; Among them, R 12 is the curvature radius of the concave surface of the first lens 100, R 72 is the curvature radius of the concave surface of the seventh lens 700.

[0046] Further, the Abbe number Abbe of the seventh lens 700 satisfies 30<ABBE<40.

[0047] Furthermore, an aperture stop is provided between the sixth lens 600 and the seventh lens 700, and the aperture stop is used to control the light flux and correct the aberration.

[0048] In some specific embodiments of the present invention, the fourth lens group G4 further includes a ninth lens 900 and a tenth lens 110; the ninth lens 900 is a negative power lens, the tenth lens 110 is a positive power lens, the edges of the ninth lens 900 and the tenth lens 110 are glued to form a negative power lens, the ninth lens 900 is a biconcave lens, the tenth lens 110 is a biconvex lens, and the curvature radius of the concave surface of the ninth lens 900 facing the tenth lens 110 is the same as the curvature radius of the convex surface of the tenth lens 110 facing the ninth lens 900.

[0049] Furthermore, the refractive index Nd of the tenth lens 110 is 10 Satisfy 1.5<Nd 10 <1.70, the refractive index Nd of the seventh lens 700 70 Meet Nd 70 >1.8.

[0050] In some specific embodiments of the present invention, the fourth lens group G4 further includes an eleventh lens 120, the eleventh lens 120 is a biconvex lens and a positive power lens, the first lens 100 and the eleventh lens 120 satisfy the following condition: 1.3<|f(100) / f(120)|<2.5; wherein f(100) is the focal length of the first lens 100, and f(120) is the focal length of the eleventh lens 120.

[0051] In some specific embodiments of the present invention, the fourth lens group G4 further includes a twelfth lens 130 . The twelfth lens 130 is a biconvex lens and a positive power lens.

[0052] In some specific embodiments of the present invention, the spectrometer 140 is a wavelength spectrometer, which can be a cubic spectrometer mirror, which is formed by gluing two 45-degree right-angle prisms, and the gluing surface is the spectrometer surface. In other embodiments, the spectrometer 140 can also be a flat plate spectrometer, but it needs to be placed at 45 degrees. The spectrometer 140 separates light of two different wavelength bands (400-760) nm and (800-1100) nm, and the optical axes of the two wavelength bands are perpendicular to each other after the spectrometer splits. In this embodiment, it is not limited to which specific wavelength band of light is a horizontal beam or a vertical beam, but the corresponding wavelength band of the filter device 150 and the identification device 160 need to correspond.

[0053] Furthermore, the Abbe number Abbe of the third lens 300 is smaller than the Abbe number Abbe of the light splitting device 140 .

[0054] In some specific embodiments of the present invention, the filtering device 150 includes a first filter 1501 and a second filter 1502. The first filter 1501 is used to receive a horizontal light beam, filter the horizontal light beam, and send the filtered horizontal light beam to the identification device 160; the second filter 1502 is used to receive a vertical light beam, filter the vertical light beam, and send the filtered vertical light beam to the identification device 160.

[0055] In some specific embodiments of the present invention, the recognition device 160 includes a first chip 1601 and a second chip 1602. The first chip 1601 is used to receive and recognize the filtered horizontal light beam, and the second chip 1602 is used to receive and recognize the filtered vertical light beam, and fuse the horizontal light beam image and the vertical light beam image through an image fusion algorithm. In this embodiment, the first chip 1601 and the second chip 1602 are both CMOS chips.

[0056] In some specific embodiments of the present invention, a first dustproof protective window sheet 1603 is provided on the first chip 1601, and a second dustproof protective window sheet 1604 is provided on the second chip 1602.

[0057] In some specific embodiments of the present invention, the optical back focus BF of the lens and the focal length of the lens satisfy BF / f>4.

[0058] Furthermore, the aperture coefficient of the lens is greater than or equal to 1.4.

[0059] Furthermore, the viewing angle of the lens is 120°.

[0060] The optical transfer function is a relatively accurate, intuitive and common way to evaluate the imaging quality of an imaging system. The higher and smoother the curve is, the better the imaging quality of the system is, and various aberrations (such as spherical aberration, coma, astigmatism, field curvature, axial chromatic aberration, vertical chromatic aberration, etc.) are well corrected.

[0061] like Figure 5 As shown in the figure, it is the optical transfer function (MTF) curve of the lens in the wide-angle state in the visible light band (400-700nm); the horizontal axis is the resolution, the unit is 1p / mm, and the vertical axis is the MTF value. Figure 5 As shown in the figure, the visible light curve drops smoothly and is concentrated. At 250p / mm, the MTF value can still be guaranteed to be greater than 0.2. This enables the system to achieve a higher pixel resolution under visible light.

[0062] like Figure 6As shown in the figure, it is the optical transfer function (MTF) curve of the lens in the wide-angle state of infrared light (800-1000nm); the horizontal axis is the resolution, the unit is 1p / mm, and the vertical axis is the MTF value. Figure 6 As shown in the figure, the infrared light curve drops smoothly and is concentrated. At 250p / mm, the MTF value can still be guaranteed to be greater than 0.2, which is generally equivalent to the visible light state.

[0063] Other structures and operations of a lens according to an embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0064] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0065] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A lens, comprising a first lens group (G1), a second lens group (G2), a third lens group (G3), a fourth lens group (G4), a light splitting device (140), a light filtering device (150) and a recognition device (160), wherein the first lens group (G1), the second lens group (G2), the third lens group (G3), the fourth lens group (G4), the light splitting device (140), the light filtering device (150) and the recognition device (160) are sequentially arranged between an object side and an imaging side; characterized in that: The light splitting device (140) is arranged between the fourth lens group (G4) and the light filtering device (150), the inlet of the light splitting device (140) is connected to the outlet of the fourth lens group (G4), and the outlet of the light splitting device (140) is connected to the inlet of the light filtering device (150), and is used to split the light beam at the outlet of the fourth lens group (G4) into a horizontal light beam and a vertical light beam, and independently send the horizontal light beam and the vertical light beam to the light filtering device (150); The filtering device (150) is arranged between the light splitting device (140) and the identification device (160), and is used to receive the horizontal light beam and the vertical light beam, filter the horizontal light beam and the vertical light beam, and independently send the filtered horizontal light beam and the vertical light beam to the identification device (160); The identification device (160) is used to receive and identify the filtered horizontal light beam and vertical light beam; The first lens group (G1) comprises a first lens (100) and a second lens (200); wherein the first lens (100) and the second lens (200) are both negative power lenses, the first lens (100) and the second lens (200) are both crescent-shaped, the convex side of the first lens (100) faces the object side, and the concave side of the first lens (100) faces the convex side of the second lens (200); The first lens (100) satisfies the following conditions: -44＜f（100）＜-25； 1.7<D1 / R2<1.82; 1.7<Nd1<1.8; Wherein, f(100) is the focal length of the first lens (100), Nd1 is the refractive index of the first lens (100), D1 is the diameter of the concave side of the first lens (100), and R2 is the radius of curvature of the concave side of the first lens (100); The second lens group (G2) comprises a third lens (300) and a fourth lens (400); wherein the edges of the third lens (300) and the fourth lens (400) are glued to form a negative power lens, the shape of the third lens (300) is a crescent shape, the fourth lens (400) is a double concave lens, the concave side of the third lens (300) faces the concave side of the second lens (200), the convex side of the third lens (300) faces the fourth lens (400), and the curvature radius of the concave side of the fourth lens (400) facing the third lens (300) is the same as the curvature radius of the convex side of the third lens (300); The fourth lens group (G4) comprises a seventh lens (700) and an eighth lens (800); wherein the edges of the seventh lens (700) and the eighth lens (800) are glued to form a positive power lens, the seventh lens (700) is a meniscus lens, the eighth lens (800) is a double convex lens, the convex side of the seventh lens (700) faces the sixth lens (600), the concave side of the seventh lens (700) faces the convex side of the eighth lens (800), and the curvature radius of the concave side of the seventh lens (700) is the same as the curvature radius of the convex side of the eighth lens (800).

2. A lens according to claim 1, characterized in that: The third lens (300), the sixth lens (600) and the seventh lens (700) satisfy the following conditions: 2.6<∣R 31 / R 61 +R 71 ∣<4; Among them, R 31 is the radius of curvature of the concave surface of the third lens (300), R 61 is the radius of curvature of the sixth lens (600) facing the fifth lens (500), R 71 is the radius of curvature of the convex surface of the seventh lens (700).

3. A lens according to claim 2, characterized in that: The first lens (100) and the seventh lens (700) satisfy the following conditions: R 12 >R 72 ; Among them, R 12 is the radius of curvature of the concave surface of the first lens (100), R 72 is the radius of curvature of the concave surface of the seventh lens (700).

4. A lens according to claim 3, characterized in that: The fourth lens group (G4) further includes a ninth lens (900) and a tenth lens (110); wherein, The edges of the ninth lens (900) and the tenth lens (110) are glued to form a negative power lens, the ninth lens (900) is a double concave lens, the tenth lens (110) is a double convex lens, and the curvature radius of the concave side of the ninth lens (900) facing the tenth lens (110) is the same as the curvature radius of the convex side of the tenth lens (110) facing the ninth lens (900).

Images