A dual-optical path telecentric lens and imaging device

Abstract

The present invention is applicable to the field of optical imaging technology, and provides a dual-optical path telecentric lens and an imaging device. The dual-optical path telecentric lens comprises: a first optical lens system and a second optical lens system, wherein the first optical lens system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a first aperture, a sixth lens, a seventh lens, an eighth lens and a ninth lens, which are sequentially arranged from an object plane to a first image plane; the second optical lens system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a second aperture, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens, which are sequentially arranged from an object plane to a second image plane; the present invention has the advantages of dual optical paths, high resolution, low distortion, achromatic design, etc., and can be connected to two different cameras at the same time to achieve different magnifications. The dual-optical path telecentric lens improves detection accuracy and meets the high-precision detection requirements of clients.

Description

Technical Field

[0001] The invention belongs to the technical field of optical imaging, and in particular relates to a dual-optical path telecentric lens and imaging equipment. Background Art

[0002] In the process of technological development, the structure of parts and components produced by modern industry has become more sophisticated and complex. These complex parts are difficult to detect with conventional detection methods. At present, mechanical vision measurement is widely used to measure high-precision complex parts. Due to the development of modern AOI (Automated Optical Inspection) detection technology, ordinary lenses cannot meet the high-precision detection needs of clients due to differences in magnification and distortion, which brings great trouble to the development of clients' detection level.

[0003] Therefore, there is an urgent need to design a dual-optical path telecentric lens that can meet customer needs. Summary of the invention

[0004] The purpose of an embodiment of the present invention is to provide a dual-path telecentric lens, aiming to solve the defects mentioned in the background technology. The present invention breaks the conventional design of existing AOI detection and adopts a dual-path telecentric optical system. The projection end is used to project a standard pattern, and the imaging end is used for pattern imaging. One lens can be connected to two different cameras at the same time to achieve different magnifications. At the same time, the dual-path telecentric optical system adopts a low distortion, large target area, and high resolution design, which greatly improves the detection accuracy of AOI and meets the client's high-precision detection requirements.

[0005] The embodiment of the present invention is implemented as follows: a dual-optical path telecentric lens comprises a first optical lens system and a second optical lens system;

[0006] The first optical lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a first aperture, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the object plane to the first image plane;

[0007] The second optical lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a second aperture, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens, which are arranged in sequence from the object plane to the second image plane;

[0008] The first optical lens system meets the following conditions:

[0009] PMAG=0.55X, F.NO=8.6, EFL=4859.7mm, TTL=287.2mm;

[0010] The second optical lens system satisfies the following conditions:

[0011] PMAG=0.158X, F.NO=6.6, EFL=3439.3mm, TTL=185.4mm;

[0012] Among them, PMAG is the magnification of the lens, X is the multiple symbol, F.NO is the relative aperture of the lens, EFL is the effective focal length of the lens, and TTL is the total optical length of the lens.

[0013] Preferably, the third lens and the fourth lens are integrally arranged to form a set of bonded lenses;

[0014] The first aperture is arranged between the fifth lens and the sixth lens, the second aperture is arranged between the fifth lens and the tenth lens, and the fifth lens is a dichroic prism.

[0015] Preferably, the first lens, the second lens, the third lens and the fourth lens constitute a front lens group, the sixth lens, the seventh lens, the eighth lens and the ninth lens constitute a first rear lens group, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens constitute a second rear lens group, the front lens group is arranged at the front end of the fifth lens, and the first rear lens group and the second rear lens group are respectively arranged at the rear end and the 90° turning point of the fifth lens;

[0016] The first optical lens system also meets the following conditions:

[0017] 50 <f1 / fa1<100;

[0018] The second optical lens system also meets the following conditions:

[0019] 100 <f2 / fa2<300;

[0020] Among them, f1 is the effective focal length of the first optical lens system, fa1 is the effective focal length of the first lens rear group, f2 is the effective focal length of the second optical lens system, and fa2 is the effective focal length of the second lens rear group.

[0021] Preferably, the lens material of the dual-optical path telecentric lens meets the following conditions:

[0022] First lens: 1.60 <Nd<1.81,45<Vd<65,

[0023] Second lens: 1.61 <Nd<1.83,40<Vd<63,

[0024] Third lens: 1.45 <Nd<1.75,45<Vd<90,

[0025] Fourth lens: 1.61 <Nd<1.91,30<Vd<63;

[0026] Sixth lens: 1.41 <Nd<1.75,45<Vd<90,

[0027] Seventh lens: 1.60 <Nd<1.85,21<Vd<50,

[0028] Eighth lens: 1.60 <Nd<1.85,40<Vd<63,

[0029] Ninth lens: 1.60 <Nd<1.85,40<Vd<63;

[0030] Tenth lens: 1.45 <Nd<1.75,45<Vd<90,

[0031] Eleventh lens: 1.70 <Nd<1.95,18<Vd<35,

[0032] 12th lens: 1.61 <Nd<1.91,40<Vd<63,

[0033] Thirteenth lens: 1.6 <Nd<1.85,40<Vd<65;

[0034] Where Nd is the refractive index coefficient and Vd is the dispersion coefficient;

[0035] As mentioned above, the material selection of the first to thirteenth lenses and the lens combination structure that satisfies these refractive index relationships are conducive to achieving a reasonable distribution of optical power, and can better balance spherical aberration, coma, and field curvature, thereby improving the resolution capability of the optical system and obtaining high-definition images; the use of materials with a lower refractive index for the lenses in the front group of the lens is conducive to reducing the production cost of the lens; the third and fourth lenses use low-refractive-index and high-refractive-index materials to form a bonded lens for better correction of lens chromatic aberration; the seventh and eighth lenses use low-dispersion materials to further correct system chromatic aberration and improve the resolution capability of the lens; the use of high-refractive-index materials for the eighth, ninth, twelfth and thirteenth lenses is conducive to reducing distortion and reducing lens telecentricity.

[0036] Preferably, the first lens is a biconvex positive lens, the curvature radii of the front and rear surfaces of the first lens are R11 and R12 respectively, and the core thickness along the optical axis is d1, wherein 100 mm <R11<300mm,-300mm<R12<300mm,3mm<d1<12mm;

[0037] The second lens is a concave-convex positive lens, the curvature radii of the front and rear surfaces of the second lens are R21 and R22 respectively, and the core thickness along the optical axis is d3, wherein 50 mm <R21<150mm,100mm<R22<300mm,3mm<d3<20mm;

[0038] The third lens is a positive lens with a plano-convex shape. The radii of curvature of the front and rear surfaces of the third lens are R31 and R32 respectively, and its core thickness along the optical axis is d5, where 10 mm < R31 < 35 mm, -100 mm < R32 < 100 mm, and 2 mm < d5 < 8 mm;

[0039] The fourth lens is a negative lens with a plano-concave shape. The radii of curvature of the front and rear surfaces of the fourth lens are R41 and R42 respectively, and its core thickness along the optical axis is d6, where -100 mm < R41 < 100 mm, 10 mm < R42 < 45 mm, and 0.7 mm < d6 < 5 mm.

[0040] Preferably, the fifth lens is a beam-splitting prism, with its dispersion coefficient Vd satisfying 45 < Vd < 75 and its refractive index coefficient Nd satisfying 1.4 < Nd < 1.75. The radii of curvature of the front and rear surfaces of the fifth lens are R51 and R52 respectively, and its core thickness along the optical axis is d8, where both R51 and R52 are flat surfaces, 5 mm < d8 < 20 mm, and the transmission ratio to reflection ratio is 5:5.

[0041] Preferably, the sixth lens is a positive lens with a plano-convex shape. The radii of curvature of the front and rear surfaces of the sixth lens are R71 and R72 respectively, and its core thickness along the optical axis is d11, where -100 mm < R71 < 100 mm, -50 mm < R72 < -10 mm, and 1 mm < d11 < 6 mm;

[0042] The seventh lens is a negative lens with a bi-concave shape. The radii of curvature of the front and rear surfaces of the seventh lens are R81 and R82 respectively, and its core thickness along the optical axis is d13, where -50 mm < R81 < -10 mm, 100 mm < R82 < 300 mm, and 2 mm < d13 < 15 mm;

[0043] The eighth lens is a positive lens with a convex-concave shape. The radii of curvature of the front and rear surfaces of the eighth lens are R91 and R92 respectively, and its core thickness along the optical axis is d15, where -50 mm < R91 < -25 mm, -50 mm < R92 < -20 mm, and 3 mm < d15 < 10 mm;

[0044] The ninth lens is a positive lens with a bi-convex shape. The radii of curvature of the front and rear surfaces of the ninth lens are R101 and R102 respectively, and its core thickness along the optical axis is d17, where 200 mm < R101 < 50 mm, -200 mm < R102 < -50 mm, and 2.0 mm < d17 < 8 mm.

[0045] Preferably, the tenth lens is a positive meniscus lens. The radii of curvature of the front and rear surfaces of the tenth lens are R131 and R132 respectively, and its core thickness in the optical axis direction is d21, where -50 mm < R131 < -10 mm, -20 mm < R132 < -2 mm, 1.5 mm < d21 < 7 mm;

[0046] The eleventh lens is a negative biconcave lens. The radii of curvature of the front and rear surfaces of the eleventh lens are R141 and R142 respectively, and its core thickness in the optical axis direction is d23, where -20 mm < R141 < -2 mm, 100 mm < R142 < 300 mm, 1.5 mm < d23 < 7 mm;

[0047] The twelfth lens is a positive meniscus lens. The radii of curvature of the front and rear surfaces of the twelfth lens are R151 and R152 respectively, and its core thickness in the optical axis direction is d25, where -30 mm < R151 < -5 mm, -30 mm < R152 < -5 mm, 1.5 mm < d25 < 7 mm;

[0048] The thirteenth lens is a positive biconvex lens. The radii of curvature of the front and rear surfaces of the thirteenth lens are R161 and R162 respectively, and its core thickness in the optical axis direction is d27, where 50 mm < R161 < 200 mm, -50 mm < R162 < -10 mm, 1.5 mm < d27 < 7 mm;

[0049] The fourteenth lens is a plano lens. Its Abbe number Vd satisfies 45 < Vd < 75, and its refractive index Nd satisfies 1.4 < Nd < 1.75. The radii of curvature of the front and rear surfaces of the fourteenth lens are R171 and R172 respectively, and its core thickness in the optical axis direction is d29, where both R171 and R172 are flat surfaces, and 5 mm < d29 < 20 mm.

[0050] For the convenience of implementation, popularization and application of the above, another object of the embodiments of the present invention is to provide an imaging device. The imaging device includes a camera and the dual-path telecentric lens as described above. The two cameras are respectively arranged on the first image plane and the second image plane of the dual-path telecentric lens.

[0051] The dual-path telecentric lens provided in the above embodiment has an object plane, a first image plane, and a second image plane through the first optical lens system and the second optical lens system. It breaks the conventional design of existing AOI detection and adopts a dual-path telecentric optical structure. The first image plane can be used as a projection end to project standard patterns, and the second image plane can be used as an imaging end for pattern imaging. Such a lens can be connected to two different cameras at the same time to achieve different magnifications. At the same time, the dual-path telecentric optical structure adopts a low distortion, large target surface, and high resolution design, which greatly improves the detection accuracy of existing AOI and meets the high-precision detection requirements of the client. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic structural diagram of a dual-optical path telecentric lens provided in an embodiment of the present invention.

[0053] Figure 2 Schematic diagram of the assembly of a dual-optical path telecentric lens in an embodiment of the present invention.

[0054] Figure 3 Schematic diagram of the MTF of the dual-optical path telecentric lens in an embodiment of the present invention.

[0055] Figure 4 Schematic diagram of the distortion of the dual-optical path telecentric lens in an embodiment of the present invention.

[0056] Figure 5 1 is a point diagram of a dual-optical-path telecentric lens in an embodiment of the present invention.

[0057] Figures 6 to 19 Schematic diagram of a lens in an embodiment of the present invention.

[0058] In the accompanying drawings: 1-first lens; 2-second lens; 3-third lens; 4-fourth lens; 5-fifth lens; 6-first aperture; 7-sixth lens; 8-seventh lens; 9-eighth lens; 10-ninth lens; 11-first image plane; 12-second aperture; 13-tenth lens; 14-eleventh lens; 15-twelfth lens; 16-thirteenth lens; 17-fourteenth lens; 18-second image plane; OBJ-object plane. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0060] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0061] Figure 1A schematic structural diagram of a dual-optical-path telecentric lens provided by an embodiment of the present invention, comprising a first optical lens system and a second optical lens system;

[0062] The first optical lens system includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a first aperture 6, a sixth lens 7, a seventh lens 8, an eighth lens 9 and a ninth lens 10 which are arranged in sequence from the object plane OBJ to the first image plane 11;

[0063] The second optical lens system includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a second aperture 12, a tenth lens 13, an eleventh lens 14, a twelfth lens 15, a thirteenth lens 16 and a fourteenth lens 17 which are arranged in sequence from the object plane OBJ to the second image plane 18;

[0064] The first optical lens system meets the following conditions:

[0065] PMAG=0.55X, F.NO=8.6, EFL=4859.7mm, TTL=287.2mm;

[0066] The second optical lens system satisfies the following conditions:

[0067] PMAG=0.158X, F.NO=6.6, EFL=3439.3mm, TTL=185.4mm;

[0068] Among them, PMAG is the magnification of the lens, X is the multiple symbol, F.NO is the relative aperture of the lens, EFL is the effective focal length of the lens, and TTL is the total optical length of the lens.

[0069] In this embodiment, the optical lens system of the dual-path telecentric lens has the advantages of dual light paths, high resolution, low distortion, and achromatic design. A dual-path telecentric optical system is adopted, and one image plane is used as the projection end to project the standard pattern, and the other image plane is used as the imaging end for pattern imaging. Such a lens can be connected to two different cameras at the same time to achieve different magnifications. At the same time, the dual-path telecentric optical system adopts low distortion, large target surface, and high resolution design, which greatly improves the detection accuracy of AOI and meets the client's high-precision detection requirements.

[0070] It should be noted that the optical axis of the lens is not a real line, but a reference line in the optical sense, that is, Figure 1 The horizontal line connecting the object plane OBJ and the image plane (specifically the first image plane 11); Figure 1 , Figure 2 shown.

[0071] In an example of this embodiment, the angle between the object plane OBJ and the optical axis of the lens can be adjusted arbitrarily from 45° to 90°, and the angle between the image plane and the optical axis of the lens is adjusted accordingly according to the angle between the object plane OBJ and the optical axis of the lens.

[0072] like Figure 1 , Figure 8 , Fig. 9 As shown, in one example of this embodiment, the third lens 3 and the fourth lens 4 are integrally arranged to form a set of bonded lenses;

[0073] The first aperture 6 is arranged between the fifth lens 5 and the sixth lens 7, the second aperture 12 is arranged between the fifth lens 5 and the tenth lens 13, and the fifth lens 5 is a beam splitter prism with a transmission-reflection ratio of 5:5.

[0074] In this example, the third lens 3 (plano-convex positive lens) and the fourth lens 4 (plano-concave negative lens) are bonded to form an achromatic bonded lens. The focal points of the front lens group 100 and the first rear lens group 200 coincide with the center position of the first aperture 6, so that the double telecentric function of the lens can be realized; the focal points of the front lens group 100 and the second rear lens group 300 coincide with the center position of the second aperture 12 to realize the double telecentric function of the lens. The first aperture 6 and the second aperture 12 can also be used to adjust the spot size of the lens, control the amount of light entering, etc.

[0075] In an example of this embodiment, the third lens 3 and the fourth lens 4 can be joined by a transparent adhesive; the adhesive can be a common product on the market and is not limited here.

[0076] In an example of this embodiment, the first lens 1, the second lens 2, the third lens 3 and the fourth lens 4 constitute a front lens group 100, the sixth lens 7, the seventh lens 5, the eighth lens 9 and the ninth lens 10 constitute a first rear lens group 200, the tenth lens 13, the eleventh lens 14, the twelfth lens 15, the thirteenth lens 16 and the fourteenth lens 17 constitute a second rear lens group 300, the front lens group 100 is arranged at the front end of the fifth lens 5, and the first rear lens group 200 and the second rear lens group 300 are respectively arranged at the rear end and the 90° turning point of the fifth lens 5;

[0077] The first optical lens system also meets the following conditions:

[0078] 50 <f1 / fa1<100;

[0079] The second optical lens system also meets the following conditions:

[0080] 100 <f2 / fa2<300;

[0081] Among them, f1 is the effective focal length of the first optical lens system, fa1 is the effective focal length of the first rear lens group 200, f2 is the effective focal length of the second optical lens system, fa2 is the effective focal length of the second rear lens group 300; the effective focal length of the front lens group 100 can be recorded as fa.

[0082] In one embodiment, Figure 1 , Figure 2 As shown, the lens material of the dual-optical path telecentric lens meets the following conditions:

[0083] First lens 1: 1.60 <Nd<1.81,45<Vd<65,

[0084] Second lens 2: 1.61 <Nd<1.83,40<Vd<63,

[0085] Third lens 3: 1.45 <Nd<1.75,45<Vd<90,

[0086] Fourth lens 4:1.61 <Nd<1.91,30<Vd<63;

[0087] Sixth lens 7:1.41 <Nd<1.75,45<Vd<90,

[0088] Seventh lens 8:1.60 <Nd<1.85,21<Vd<50,

[0089] Eighth lens 9:1.60 <Nd<1.85,40<Vd<63,

[0090] Ninth lens 10:1.60 <Nd<1.85,40<Vd<63;

[0091] Tenth lens 13:1.45 <Nd<1.75,45<Vd<90,

[0092] Eleventh lens 14:1.70 <Nd<1.95,18<Vd<35,

[0093] 12th lens 15:1.61 <Nd<1.91,40<Vd<63,

[0094] Thirteenth lens 16:1.6 <Nd<1.85,40<Vd<65;

[0095] Wherein, Nd is the refractive index coefficient and Vd is the dispersion coefficient.

[0096] In an example of this embodiment, the dual-optical path telecentric lens may be a component / accessory of an optical detection device, an imaging device, or a photographic device, or may be an independent lens, but is not limited thereto.

[0097] like Figure 1 , Figure 2 , Figures 6 to 9 As shown in Figures 6 to 9 , in one embodiment, the first lens 1 is a biconvex positive lens with a dispersion coefficient Vd of 45 < Vd < 65 and a refractive index coefficient Nd of 1.60 < Nd < 1.81. The curvature radii of the front and back surfaces of the first lens 1 are R11 and R12 respectively, and its core thickness along the optical axis is d1, where 100 mm < R11 < 300 mm, -300 mm < R12 < 300 mm, and 3 mm < d1 < 12 mm;

[0098] In an example of this embodiment, R11 of the first lens 1 is 169.535 mm, R12 is -207.554 mm, d1 is 7.704 mm, and d2 is 15 mm; the refractive index coefficient Nd is 1.63, and the dispersion coefficient Vd is 55.4. d2 is the relative distance between the first lens 1 and the second lens 2.

[0099] In an example of this embodiment, for the first lens 1, the values of Nd and Vd can also be other values within the range of 1.60 < Nd < 1.81 and 45 < Vd < 65. This example is not limited to this.

[0100] In an example of this embodiment, the second lens 2 is a positive meniscus lens with a dispersion coefficient Vd of 40 < Vd < 63 and a refractive index coefficient Nd of 1.61 < Nd < 1.83. The curvature radii of the front and back surfaces of the second lens 2 are R21 and R22 respectively, and its core thickness along the optical axis is d3, where 50 mm < R21 < 150 mm, 100 mm < R22 < 300 mm, and 3 mm < d3 < 20 mm;

[0101] In a preferred example, for the second lens 2, R21 is 74.393 mm, R22 is 137.027 mm, d3 is 6.743 mm, d4 is 79.58 mm, Nd is 1.729, and Vd is 54.67. d4 is the relative distance between the second lens 2 and the third lens 3.

[0102] In an example of this embodiment, the third lens 3 is a plano-convex positive lens with a dispersion coefficient Vd of 45 < Vd < 90 and a refractive index coefficient Nd of 1.45 < Nd < 1.75. The curvature radii of the front and back surfaces of the third lens 3 are R31 and R32 respectively, and its core thickness along the optical axis is d5, where 10 mm < R31 < 35 mm, -100 mm < R32 < 100 mm, and 2 mm < d5 < 8 mm;

[0103] In a preferred example, R31 of the third lens 3 is 15.992 mm, R32 is a plane, which can be regarded as infinity, d5 is 4.7 mm, Nd is 1.49, and Vd is 81;

[0104] In an example of this embodiment, the fourth lens 4 is a plano-concave negative lens, its dispersion coefficient Vd satisfies 30 < Vd < 63, the refractive index coefficient Nd satisfies 1.61 < Nd < 1.91, the curvature radii of the front and rear surfaces of the fourth lens 4 are R41 and R42 respectively, and its core thickness along the optical axis direction is d6, where -100 mm < R41 < 100 mm, 10 mm < R42 < 45 mm, 0.7 mm < d6 < 5 mm;

[0105] In a preferred example, R41 of the fourth lens 4 is a plane, R42 is 19.993 mm, d6 is 1.361 mm, d7 is 2.88 mm, d7 is the relative distance between the fourth lens 4 and the fifth lens 5, Nd is 1.72, Vd is 37.99, and the third lens 3 and the fourth lens 4 are bonded together to form a bonded achromatic lens.

[0106] As Figure 1 、 Fig.10 shown, in an embodiment, the fifth lens 5 is a beam splitting prism, its dispersion coefficient Vd satisfies 45 < Vd < 75, the refractive index coefficient Nd satisfies 1.4 < Nd < 1.75, the curvature radii of the front and rear surfaces of the fifth lens 5 are R51 and R52 respectively, and its core thickness along the optical axis direction is d8, where both R51 and R52 are planes, 5 mm < d8 < 20 mm, and the transmission ratio is 5:5.

[0107] In an example of this embodiment, in the beam splitting prism, R51 is a plane, R52 is a plane, d8 is 13 mm; d9 is 2.5 mm, and d10 is 2 mm. Where d9 is the relative distance between the fifth lens 5 and the first diaphragm 6, and d10 is the relative distance between the first diaphragm 6 and the sixth lens 7.

[0108] In an alternative example, the transmission ratio of the beam splitting prism is not limited to 5:5, and can be 6:4 or 4:6, etc.

[0109] In an example, the beam splitting prism can be installed on the optical axis of the lens through a rotating shaft and a mounting frame. One end of the rotating shaft is connected to a micro motor, and automatic driving is achieved through the micro motor, so that the rotating shaft and the beam splitting prism can be deflected, and further the adjustment of the transmission ratio can be realized.

[0110] As Figure 1 、 Figure 2 、 Figures 11 to 19As shown, in one embodiment, the sixth lens 7 is a plano-convex positive lens, with its dispersion coefficient Vd satisfying 45 < Vd < 90 and refractive index coefficient Nd satisfying 1.41 < Nd < 1.75. The curvature radii of the front and rear surfaces of the sixth lens 7 are R71 and R72 respectively, and its core thickness along the optical axis direction is d11, where -100 mm < R71 < 100 mm, -50 mm < R72 < -10 mm, and 1 mm < d11 < 6 mm;

[0111] In a preferred embodiment, R71 of the sixth lens 7 is a plane, R72 is -35.729 mm, d11 is 2.38 mm, d12 is 3.13 mm, Nd is 1.48, and Vd is 81. Here, d12 is the relative distance between the sixth lens 7 and the seventh lens 8.

[0112] In an example of this embodiment, the seventh lens 8 is a biconcave negative lens, with its dispersion coefficient Vd satisfying 21 < Vd < 50 and refractive index coefficient satisfying 1.60 < Nd < 1.85. The curvature radii of the front and rear surfaces of the seventh lens 8 are R81 and R82 respectively, and its core thickness along the optical axis direction is d13, where -50 mm < R81 < -10 mm, 100 mm < R82 < 300 mm, and 2 mm < d13 < 15 mm;

[0113] In a preferred example, R81 of the seventh lens 8 is -15.154 mm, R82 is 214.85 mm, d13 is 10.04 mm, d14 is 10.7 mm, Nd is 1.64, and Vd is 33.84. Here, d14 is the relative distance between the seventh lens 8 and the eighth lens 9.

[0114] In this example, for the seventh lens 8, the values of Nd and Vd can also be other values within the range of 1.60 < Nd < 1.85 and 21 < Vd < 50. This example is not limited to this.

[0115] In an example of this embodiment, the eighth lens 9 is a convex-concave positive lens, with its dispersion coefficient Vd satisfying 40 < Vd < 63 and refractive index coefficient Nd satisfying 1.60 < Nd < 1.85. The curvature radii of the front and rear surfaces of the eighth lens 9 are R91 and R92 respectively, and its core thickness along the optical axis direction is d15, where -50 mm < R91 < -25 mm, -50 mm < R92 < -20 mm, and 3 mm < d15 < 10 mm;

[0116] In a preferred example, R91 of the eighth lens 9 is -65.669 mm, R92 is -29.096 mm, d15 is 8.04 mm, d16 is 29.05 mm, Nd is 1.77, and Vd is 49.62; here, d16 is the relative distance between the eighth lens 9 and the ninth lens 10.

[0117] In an example of this embodiment, the ninth lens 10 is a biconvex positive lens, with its dispersion coefficient Vd satisfying 40 < Vd < 63, refractive index coefficient Nd satisfying 1.60 < Nd < 1.85. The radius of curvature of the front and rear surfaces of the ninth lens 10 are R101 and R102 respectively, its core thickness along the optical axis direction is d17, where 200mm < R101 < 50mm, -200mm < R102 < -50mm, and 2.0mm < d17 < 8mm.

[0118] In a preferred example, R101 of the ninth lens 10 is 161.675mm, R102 is -97.755mm, d17 is 7.54mm, d18 is 78.58mm, Nd is 1.71, and Vd is 53.93. Where d18 is the relative distance between the ninth lens 10 and the first image plane 11.

[0119] In an example of this embodiment, the tenth lens 13 is a positive meniscus lens, with its dispersion coefficient Vd satisfying 45 < Vd < 90, refractive index coefficient Nd satisfying 1.45 < Nd < 1.75. The radius of curvature of the front and rear surfaces of the tenth lens 13 are R131 and R132 respectively, its core thickness along the optical axis direction is d21, where -50mm < R131 < -10mm, -20mm < R132 < -2mm, and 1.5mm < d21 < 7mm;

[0120] In a preferred example, R131 of the tenth lens 13 is -19.713mm, R132 is -4.975mm, d21 is 2.48mm, d22 is 0.64mm, Nd is 1.59, and Vd is 68.34; where d22 is the relative distance between the tenth lens 13 and the eleventh lens 14.

[0121] In an example of this embodiment, the relative distance between the fifth lens 5 and the second aperture stop 12 is d19, and the relative distance between the second aperture stop 12 and the tenth lens 13 is d20; d19 and d20 in this example can be set as required and will not be elaborated here.

[0122] In an example of this embodiment, the eleventh lens 14 is a biconcave negative lens, with its dispersion coefficient Vd satisfying 18 < Vd < 35, refractive index coefficient Nd satisfying 1.70 < Nd < 1.95; the radius of curvature of the front and rear surfaces of the eleventh lens 14 are R141 and R142 respectively, its core thickness along the optical axis direction is d23, where -20mm < R141 < -2mm, 100mm < R142 < 300mm, and 1.5mm < d23 < 7mm;

[0123] In a preferred example, R141 of the eleventh lens 14 is -4.274 mm, R142 is 183.801 mm, d23 is 4.248 mm, d24 is 2.63 mm, Nd is 1.71, and Vd is 29.5. Among them, d24 is the relative distance between the eleventh lens 14 and the twelfth lens 15.

[0124] In an example of this embodiment, the twelfth lens 15 is a convex-concave positive lens, with its dispersion coefficient Vd satisfying 40 < Vd < 63, refractive index coefficient Nd satisfying 1.61 < Nd < 1.91. The curvature radii of the front and rear surfaces of the twelfth lens 15 are R151 and R152 respectively, and its core thickness along the optical axis direction is d25, where -30 mm < R151 < -5 mm, -30 mm < R152 < -5 mm, and 1.5 mm < d25 < 7 mm;

[0125] In a preferred example, R151 of the twelfth lens 15 is -16.044 mm, R152 is -11.09 mm, d25 is 3.33 mm, d26 is 0.5 mm, Nd is 1.83, and Vd is 42.7; where d26 is the relative distance between the twelfth lens 15 and the thirteenth lens 16.

[0126] In an example of this embodiment, the thirteenth lens 16 is a biconvex positive lens, with its dispersion coefficient Vd satisfying 40 < Vd < 65, refractive index coefficient Nd satisfying 1.6 < Nd < 1.85. The curvature radii of the front and rear surfaces of the thirteenth lens 16 are R161 and R162 respectively, and its core thickness along the optical axis direction is d27, where 50 mm < R161 < 200 mm, -50 mm < R162 < -10 mm, and 1.5 mm < d27 < 7 mm;

[0127] In a preferred example, R161 of the thirteenth lens 16 is 118.986 mm, R162 is -18.4 mm, d27 is 3.86 mm, d28 is 17.234 mm, Nd is 1.80, and Vd is 46.5; where d28 is the relative distance between the thirteenth lens 16 and the fourteenth lens 17.

[0128] In an example of this embodiment, the fourteenth lens 17 is a plano lens, with its dispersion coefficient Vd satisfying 45 < Vd < 75, refractive index coefficient Nd satisfying 1.4 < Nd < 1.75. The curvature radii of the front and rear surfaces of the fourteenth lens 17 are R171 and R172 respectively, and its core thickness along the optical axis direction is d29, where both R171 and R172 are planes, and 5 mm < d29 < 20 mm.

[0129] In a preferred example, d29 is 13 mm, d30 is 0.045 mm, Nd is 1.51, and Vd is 64.19; wherein d30 is the relative distance between the fourteenth lens 17 and the second image plane 18 .

[0130] It should be noted that the data from d1 to d18 or d19 to d30 in some of the above examples are only preferred items in different examples, and the preferred items in these examples do not necessarily exist at the same time.

[0131] In an example of this embodiment, the optical performance of the dual-optical path telecentric lens is verified. Figure 3 Schematic diagram of MTF of a dual-optical-path telecentric lens in an embodiment of the present invention; Figure 4 Schematic diagram of distortion of a dual-optical-path telecentric lens in an embodiment of the present invention; Figure 5 is a point diagram of a dual-optical-path telecentric lens in an embodiment of the present invention;

[0132] Depend on Figures 3 to 5 It can be seen that Figure 3 In the figure, the horizontal axis represents the spatial frequency of line pairs / mm (lp / mm), and the vertical axis represents the OTF value. The higher the curve, the better the imaging quality. The full name of OTF is optical transfer function. Figure 3 It can be seen that the present embodiment exhibits good contrast within a spatial frequency of 100lp / mm, which indicates that the comprehensive resolution level of the present embodiment is high; Figure 4 In the distortion diagram in , it is a vertical axis aberration, which only changes the position of the off-axis imaging convergence point and does not affect the clarity of the image; Figure 5 It can be seen that the imaging points under each field of view almost converge into an ideal point, indicating that this embodiment has good imaging performance. The lens of this embodiment has excellent optical performance, and has the advantages of large target surface, high resolution, and double telecentricity.

[0133] The working principle of this embodiment is: adopting the object-side and image-side telecentric design, collecting light through the front lens group 100 and then dividing it into two beams through a dichroic prism and entering different rear groups respectively, namely the first rear lens group 200 and the second rear lens group 300; different magnifications are obtained through the aberration correction of different rear lens groups, and at the same time, a 13mm thick glass sheet can be inserted at the other end of the imaging to simulate the device of the projector to realize the imaging and projection functions; this embodiment not only has a simple structure and is easy to manufacture, but also effectively corrects the secondary spectral chromatic aberration to meet the actual usage conditions of customers.

[0134] In another embodiment, an imaging device includes a camera and the dual-optical-path telecentric lens as described above, wherein two cameras are respectively arranged on a first image plane 10 and a second image plane 18 of the dual-optical-path telecentric lens.

[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual optical path telecentric lens, characterized in that: comprising a first optical lens system and a second optical lens system; The first optical lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a first aperture, a sixth lens, a seventh lens, an eighth lens and a ninth lens which are arranged in sequence from the object plane to the first image plane; The second optical lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a second aperture, a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens and a fourteenth lens, which are arranged in sequence from the object plane to the second image plane; The first optical lens system meets the following conditions: PMAG=0.55X, F.NO = 8.6, EFL=4859.7mm, TTL=287.2mm; The second optical lens system satisfies the following conditions: PMAG=0.158X, F.NO = 6.6, EFL=3439.3mm, TTL=185.4mm; Among them, PMAG is the magnification of the lens, F.NO is the relative aperture of the lens, EFL is the effective focal length of the lens, and TTL is the total optical length of the lens; The first lens, the second lens, the third lens and the fourth lens constitute a front lens group, the sixth lens, the seventh lens, the eighth lens and the ninth lens constitute a first rear lens group, the tenth lens, the eleventh lens, the twelfth lens, the thirteenth lens and the fourteenth lens constitute a second rear lens group, the front lens group is arranged at the front end of the fifth lens, and the first rear lens group and the second rear lens group are respectively arranged at the rear end and the 90° turning point of the fifth lens; The first optical lens system also meets the following conditions: 50 <f1 / fa1<100; The second optical lens system also meets the following conditions: 100 <f2 / fa2<300; Among them, f1 is the effective focal length of the first optical lens system, fa1 is the effective focal length of the first lens rear group, f2 is the effective focal length of the second optical lens system, and fa2 is the effective focal length of the second lens rear group.

2. The dual optical path telecentric lens according to claim 1, characterized in that: The third lens and the fourth lens are integrally arranged to form a set of bonded lenses; The first aperture is arranged between the fifth lens and the sixth lens, the second aperture is arranged between the fifth lens and the tenth lens, and the fifth lens is a dichroic prism.

3. The dual optical path telecentric lens according to claim 1, characterized in that: The lens material of the dual-optical path telecentric lens meets the following conditions: First lens: 1.60 <Nd<1.81,45<Vd<65, Second lens: 1.61 <Nd<1.83,40<Vd<63, Third lens: 1.45 <Nd<1.75,45<Vd<90, Fourth lens: 1.61 <Nd<1.91,30<Vd<63; Sixth lens: 1.41 <Nd<1.75,45<Vd<90, Seventh lens: 1.60 <Nd<1.85,21<Vd<50, Eighth lens: 1.60 <Nd<1.85,40<Vd<63, Ninth lens: 1.60 <Nd<1.85,40<Vd<63; Tenth lens: 1.45 <Nd<1.75,45<Vd<90, The eleventh lens: 1.70 < Nd < 1.95, 18 < Vd < 35, The twelfth lens: 1.61 < Nd < 1.91, 40 < Vd < 63, The thirteenth lens: 1.6 < Nd < 1.85, 40 < Vd < 65; wherein, Nd is the refractive index coefficient and Vd is the dispersion coefficient.

4. The dual optical path telecentric lens according to claim 1, characterized in that: The first lens is a biconvex positive lens. The curvature radii of the front and rear surfaces of the first lens are R11 and R12 respectively, and its core thickness along the optical axis is d1, where 100 mm < R11 < 300 mm, -300 mm < R12 < 300 mm, 3 mm < d1 < 12 mm; The second lens is a meniscus positive lens. The curvature radii of the front and rear surfaces of the second lens are R21 and R22 respectively, and its core thickness along the optical axis is d3, where 50 mm < R21 < 150 mm, 100 mm < R22 < 300 mm, 3 mm < d3 < 20 mm; The third lens is a plano-convex positive lens. The curvature radii of the front and rear surfaces of the third lens are R31 and R32 respectively, and its core thickness along the optical axis is d5, where 10 mm < R31 < 35 mm, -100 mm < R32 < 100 mm, 2 mm < d5 < 8 mm; The fourth lens is a plano-concave negative lens. The curvature radii of the front and rear surfaces of the fourth lens are R41 and R42 respectively, and its core thickness along the optical axis is d6, where -100 mm < R41 < 100 mm, 10 mm < R42 < 45 mm, 0.7 mm < d6 < 5 mm.

5. The dual optical path telecentric lens according to claim 1 or 4, characterized in that: The fifth lens is a beam-splitting prism. Its dispersion coefficient Vd is 45 < Vd < 75, and its refractive index coefficient Nd is 1.4 < Nd < 1.

75. The curvature radii of the front and rear surfaces of the fifth lens are R51 and R52 respectively, and its core thickness along the optical axis is d8, where R51 and R52 are both flat surfaces, 5 mm < d8 < 20 mm, and the transmission ratio is 5:

5.

6. The dual-optical-path telecentric lens according to claim 1 or 4, characterized in that: The sixth lens is a plano-convex positive lens. The curvature radii of the front and rear surfaces of the sixth lens are R71 and R72 respectively, and its core thickness along the optical axis is d11, where -100 mm < R71 < 100 mm, -50 mm < R72 < -10 mm, 1 mm < d11 < 6 mm; The seventh lens is a biconcave negative lens. The curvature radii of the front and rear surfaces of the seventh lens are R81 and R82 respectively, and its core thickness along the optical axis is d13, where -50 mm < R81 < -10 mm, 100 mm < R82 < 300 mm, 2 mm < d13 < 15 mm; The eighth lens is a meniscus positive lens. The curvature radii of the front and rear surfaces of the eighth lens are R91 and R92 respectively, and its core thickness along the optical axis is d15, where -50 mm < R91 < -25 mm, -50 mm < R92 < -20 mm, 3 mm < d15 < 10 mm; The ninth lens is a biconvex positive lens. The curvature radii of the front and rear surfaces of the ninth lens are R101 and R102 respectively. Its core thickness along the optical axis direction is d17, where 200 mm < R101 < 50 mm, -200 mm < R102 < -50 mm, and 2.0 mm < d17 < 8 mm.

7. The dual-optical-path telecentric lens according to claim 6, characterized in that: The tenth lens is a positive meniscus lens. The curvature radii of the front and rear surfaces of the tenth lens are R131 and R132 respectively. Its core thickness along the optical axis direction is d21, where -50 mm < R131 < -10 mm, -20 mm < R132 < -2 mm, and 1.5 mm < d21 < 7 mm; The eleventh lens is a biconcave negative lens. The curvature radii of the front and rear surfaces of the eleventh lens are R141 and R142 respectively. Its core thickness along the optical axis direction is d23, where -20 mm < R141 < -2 mm, 100 mm < R142 < 300 mm, and 1.5 mm < d23 < 7 mm; The twelfth lens is a positive meniscus lens. The curvature radii of the front and rear surfaces of the twelfth lens are R151 and R152 respectively. Its core thickness along the optical axis direction is d25, where -30 mm < R151 < -5 mm, -30 mm < R152 < -5 mm, and 1.5 mm < d25 < 7 mm; The thirteenth lens is a biconvex positive lens. The curvature radii of the front and rear surfaces of the thirteenth lens are R161 and R162 respectively. Its core thickness along the optical axis direction is d27, where 50 mm < R161 < 200 mm, -50 mm < R162 < -10 mm, and 1.5 mm < d27 < 7 mm.

8. The dual-optical-path telecentric lens according to claim 7, characterized in that: The fourteenth lens is a plano lens. Its dispersion coefficient Vd satisfies 45 < Vd < 75, and its refractive index coefficient Nd satisfies 1.4 < Nd < 1.

75. The curvature radii of the front and rear surfaces of the fourteenth lens are R171 and R172 respectively. Its core thickness along the optical axis direction is d29, where both R171 and R172 are flat surfaces, and 5 mm < d29 < 20 mm.

9. An imaging device, characterized in that: It includes the dual-path telecentric lens according to any one of claims 1-8.

Images